100 research outputs found
Probing variability patterns of the Fe K line complex in bright nearby AGNs
The unprecedented sensitivity of current X-ray telescopes allows for the
first time to address the issue of the Fe K line complex variability patterns
in bright, nearby AGNs. We examine XMM-Newton observations of the brightest
sources of the FERO sample of radio-quiet type 1 AGNs with the aim of
characterizing the temporal behaviour of Fe K complex features. A systematic
mapping of residual flux above and below the continuum in the 4-9 keV range is
performed in the time vs energy domain, with the purpose of identifying
interesting spectral features in the three energy bands: 5.4-6.1 keV, 6.1-6.8
keV and 6.8-7.2 keV, corresponding respectively to the redshifted, rest frame
and blueshifted or highly ionized Fe Kalpha line bands. The variability
significance is assessed by extracting light curves and comparing them with
MonteCarlo simulations. The time-averaged profile of the Fe K complex revealed
spectral complexity in several observations. Red- and blue-shifted components
(either in emission or absorption) were observed in 30 out of 72 observations,
with an average ~90 eV for emission and ~ -30 eV for absorption
features. We detected significant line variability (with confidence levels
ranging between 90% and 99.7%) within at least one of the above energy bands in
26 out of 72 observations on time scales of ~6-30 ks. Reliability of these
features has been carefully calculated using this sample and has been assessed
at ~3sigma confidence level. This work increases the currently scanty number of
detections of variable, energy shifted, Fe lines and confirms the reliability
of the claimed detections. We found that the distribution of detected features
is peaked at high variability significances in the red- and blue-shifted energy
bands, suggesting an origin in a relativistically modified accretion flow.Comment: Accepted for publication in Astronomy & Astrophysic
Saddle Club 1988-89 Roster
A roster of 1988-89 riding and non-riding members of the Saddle Club, with officer positions enumerated
Molecular interactions between the specialist herbivore Manduca sexta (Lepidoptera, Sphigidae) and its natural host Nicotiana attenuata. VIII. An unbiased GCxGC-ToFMS analysis of the plant´s elicited volatile emissions
Treating wounds in Nicotiana attenuata leaves with Manduca sexta oral secretions (W+OS) mimics most changes elicited by M. sexta herbivory, but an unbiased analysis of the effect of the different OS constituents on volatile emissions is lacking. We used two-dimensional gas chromatography/time-of-flight (GCxGC-ToF) mass spectrometry combined with multivariate statistics to parse volatiles into regulatory patterns. Volatiles released by wounding alone and by the alkalinity of OS were assessed by applying a buffer known to mimic the pH-mediated changes of OS elicitation (pectin methyl esterase activation and methanol release). The activities of fatty acid amino acid conjugates, well-known elicitors of antiherbivore defenses, and of 2-hydroxyoctadecatrienoic acid, a newly discovered signal in OS, were determined. Approximately 400 analytes were detected after deconvolution and alignment of GCxGC data; 35 volatiles were significantly regulated upon W+OS. Two-thirds of these were specifically regulated by OS, being either amplified (most terpenoids and certain hexenylesters) or strongly repressed (many short-chain alcohols and some aromatic and hexenylester derivatives). Fatty acid amino acid conjugates played a central role in this pattern of regulation, since they induced the emission of half of OS-elicited volatiles and inhibited the production of almost all OS-repressed volatiles; 2-hydroxyoctadecatrienoic acid influenced emission of trans-α-bergamotene, while other unknown OS constituents amplified hexenylester production. We conclude that the complex bouquet of herbivory-elicited volatiles results from the complex modulations of the wound response by diverse cues found in OS. This work also underscores the value of ultra-high-resolution GCxGC-ToF analysis combined with the nontargeted mining of the resulting data
Desempenho de genótipos de feijoeiro com altos teores de ferro e zinco sob deficiência hídrica e irrigação adequada.
O trabalho objetivou identificar genótipos de feijoeiro comum mais tolerantes à deficiência hídrica, como suporte para programas de seleção de genótipos que visam o desenvolvimento de cultivares para regiões com baixa disponibilidade de chuva e com valor agregado nos grãos pelos altos teores de ferro e zinco.CONAFE
Host species composition influences infection severity among amphibians in the absence of spillover transmission
Wildlife epidemiological outcomes can depend strongly on the composition of an ecological community, particularly when multiple host species are affected by the same pathogen. However, the relationship between host species richness and disease risk can vary with community context and with the degree of spillover transmission that occurs among co‐occurring host species. We examined the degree to which host species composition influences infection by Batrachochytrium dendrobatidis (Bd), a widespread fungal pathogen associated with amphibian population declines around the world, and whether transmission occurs from one highly susceptible host species to other co‐occurring host species. By manipulating larval assemblages of three sympatric amphibian species in the laboratory, we characterized the relationship between host species richness and infection severity, whether infection mediates growth and survivorship differently across various combinations of host species, and whether Bd is transmitted from experimentally inoculated tadpoles to uninfected tadpoles. We found evidence of a dilution effect where Bd infection severity was dramatically reduced in the most susceptible of the three host species (Anaxyrus boreas). Infection also mediated survival and growth of all three host species such that the presence of multiple host species had both positive (e.g., infection reduction) and negative (e.g., mortality) effects on focal species. However, we found no evidence that Bd infection is transmitted by this species. While these results demonstrate that host species richness as well as species identity underpin infection dynamics in this system, dilution is not the product of reduced transmission via fewer infectious individuals of a susceptible host species. We discuss various mechanisms, including encounter reduction and antagonistic interactions such as competition and opportunistic cannibalism that may act in concert to mediate patterns of infection severity, growth, and mortality observed in multihost communities.There are many ways in which infection can be influenced by species diversity. Here we show experimentally that the interactions between species in a multi‐host amphibian community drive the severity of infection by the amphibian chytrid fungus. We find no evidence that infection is transmitted between two host species in our study, suggesting that spillover infection is not a cause of dilution effects in this system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111214/1/ece31385.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/111214/2/ece31385-sup-0001-FigureS1.pd
Comportamento, adaptabilidade e estabilidade de genótipos de feijoeiro comum no Nordeste brasileiro.
Diversas linhagens avançadas e variedades comerciais dos grupos comerciais carioca, mulatinho e preto de feijoeiro comum foram valiadas em diversas localidades dos estados da Bahia, Sergipe e Alagoas, no decorrer dos anos agrícolas de 2003 e 2004, em blocos ao acaso, com três repetições, visando conhecer o comportamento, a adaptabilidade e a estabilidade desses materiais para fins de exploração comercial. No município de Simão Dias,SE, os ensaios foram realizados nos sistemas em monocultivo e consorciado com o milho. Essa região mostrou-se mais propícia ao desenvolvimento do cultivo do feijoeiro comum, mostrando as maiores produtividades de grãos. O comportamento dos genótipos de feijoeiro nos sistemas em monocultivo e consorciado com o milho foi inconsistente, na maioria dos ensaios, revelando que a seleção de genótipos para o sistema consorciado não pode ser realizado no monocultivo. Os genótipos avaliados, dos diferentes grupos omerciais, mostraram-se diferentes quanto à adaptabilidade e à estabilidade de produção. As linhagens CNFM 7958 e CNFM 10375, do grupo mulatinho, evidenciaram melhor adaptação, além de expressarem adaptabilidade ampla, consolidando-se em alternativas importantes para a agricultura regional.bitstream/item/34048/1/bp-11.pd
The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] < -3.5
We present a homogeneous chemical abundance analysis of 16 elements in 190
metal-poor Galactic halo stars (38 program and 152 literature objects). The
sample includes 171 stars with [Fe/H] < -2.5, of which 86 are extremely metal
poor, [Fe/H] < -3.0. Our program stars include ten new objects with [Fe/H] <
-3.5. We identify a sample of "normal" metal-poor stars and measure the trends
between [X/Fe] and [Fe/H], as well as the dispersion about the mean trend for
this sample. Using this mean trend, we identify objects that are chemically
peculiar relative to "normal" stars at the same metallicity. These chemically
unusual stars include CEMP-no objects, one star with high [Si/Fe], another with
high [Ba/Sr], and one with unusually low [X/Fe] for all elements heavier than
Na. The Sr and Ba abundances indicate that there may be two nucleosynthetic
processes at lowest metallicity that are distinct from the main r-process.
Finally, for many elements, we find a significant trend between [X/Fe] versus
Teff which likely reflects non-LTE and/or 3D effects. Such trends demonstrate
that care must be exercised when using abundance measurements in metal-poor
stars to constrain chemical evolution and/or nucleosynthesis predictions.Comment: Accepted for publication in Ap
Turmeric (Curcuma longa Linn.) as a phytogenic growth promoter alternative for antibiotic and comparable to mannan oligosaccharides for broiler chicks
This work aimed at investigating the potential as a growth enhancer of different dietary concentrations of turmeric (Curcuma longa Linn.) as an alternative to oxytetracyline and antibiotics and as comparable to mannan oligosaccharide for broiler chicks. A total of 252 Hubbard broiler chicks at one day of age were distributed randomly in a straight run experimental design among six treatments, each replicated seven times, with six unsexed chicks per replicate. The basal diet was administered without supplements (control group) or supplemented with turmeric at 0.5, 1, and 2 g/kg diet, or with mannan oligosacride (MOS) at 1 g/kg feed or with oxytetracycline (OTC) at 50 mg/kg feed. Growth performance, carcass characteristics, meat quality traits, blood biochemical constituents, antioxidant status and red blood cell (RBCs) were investigated. Turmeric supplementation at 1 g/kg feed significantly improved feed conversion ratio (FCR) and European production index compared to the control group and MOS groups. The results indicated that turmeric can be used at 1 kg/t feed as a phytogenic feed additive as an alternative to OTC or MOS without negative effects on the productive and economic traits of broilers. There were no differences from using OTC and MOS, while there was an increase in the European production efficiency index and the broilers’ health status.This work aimed at investigating the potential as a growth enhancer of different dietary concentrations of turmeric (Curcuma longa Linn.) as an alternative to oxytetracyline and antibiotics and as comparable to mannan oligosaccharide for broiler chicks. A total of 252 Hubbard broiler chicks at one day of age were distributed randomly in a straight run experimental design among six treatments, each replicated seven times, with six unsexed chicks per replicate. The basal diet was administered without supplements (control group) or supplemented with turmeric at 0.5, 1, and 2 g/kg diet, or with mannan oligosacride (MOS) at 1 g/kg feed or with oxytetracycline (OTC) at 50 mg/kg feed. Growth performance, carcass characteristics, meat quality traits, blood biochemical constituents, antioxidant status and red blood cell (RBCs) were investigated. Turmeric supplementation at 1 g/kg feed significantly improved feed conversion ratio (FCR) and European production index compared to the control group and MOS groups. The results indicated that turmeric can be used at 1 kg/t feed as a phytogenic feed additive as an alternative to OTC or MOS without negative effects on the productive and economic traits of broilers. There were no differences from using OTC and MOS, while there was an increase in the European production efficiency index and the broilers’ health status
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