6,298 research outputs found

    Spectral decomposition of starbursts and AGNs in 5-8 micron Spitzer IRS spectra of local ULIRGs

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    We present an analysis of the 5-8 micron Spitzer-IRS spectra of a sample of 68 local Ultraluminous Infrared Galaxies (ULIRGs). Our diagnostic technique allows a clear separation of the active galactic nucleus (AGN) and starburst (SB) components in the observed mid-IR emission, and a simple analytic model provides a quantitative estimate of the AGN/starburst contribution to the bolometric luminosity. We show that AGNs are ~30 times brighter at 6 micron than starbursts with the same bolometric luminosity, so that even faint AGNs can be detected. Star formation events are confirmed as the dominant power source for extreme infrared activity, since ~85% of ULIRG luminosity arises from the SB component. Nonetheless an AGN is present in the majority (46/68) of our sources.Comment: 5 Pages, 3 figures. MNRAS Letters, Accepte

    Hyperosmotic priming of arabidopsis seedlings establishes a long-term somatic memory accompanied by specific changes of the epigenome

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    <p>Background: In arid and semi-arid environments, drought and soil salinity usually occur at the beginning and end of a plant's life cycle, offering a natural opportunity for the priming of young plants to enhance stress tolerance in mature plants. Chromatin marks, such as histone modifications, provide a potential molecular mechanism for priming plants to environmental stresses, but whether transient exposure of seedlings to hyperosmotic stress leads to chromatin changes that are maintained throughout vegetative growth remains unclear.</p> <p>Results: We have established an effective protocol for hyperosmotic priming in the model plant Arabidopsis, which includes a transient mild salt treatment of seedlings followed by an extensive period of growth in control conditions. Primed plants are identical to non-primed plants in growth and development, yet they display reduced salt uptake and enhanced drought tolerance after a second stress exposure. ChIP-seq analysis of four histone modifications revealed that the priming treatment altered the epigenomic landscape; the changes were small but they were specific for the treated tissue, varied in number and direction depending on the modification, and preferentially targeted transcription factors. Notably, priming leads to shortening and fractionation of H3K27me3 islands. This effect fades over time, but is still apparent after a ten day growth period in control conditions. Several genes with priming-induced differences in H3K27me3 showed altered transcriptional responsiveness to the second stress treatment.</p> <p>Conclusion: Experience of transient hyperosmotic stress by young plants is stored in a long-term somatic memory comprising differences of chromatin status, transcriptional responsiveness and whole plant physiology.</p&gt

    The blue sky of GJ3470b: the atmosphere of a low-mass planet unveiled by ground-based photometry

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    GJ3470b is a rare example of a "hot Uranus" transiting exoplanet orbiting a nearby M1.5 dwarf. It is of crucial interest for atmospheric studies because it is one of the most inflated low-mass planets known, bridging the boundary between "super-Earths" and Neptunian planets. We present two new ground-based light curves of GJ3470b gathered by the LBC camera at the Large Binocular Telescope. Simultaneous photometry in the ultraviolet (lambda_c = 357.5 nm) and optical infrared (lambda_c = 963.5 nm) allowed us to detect a significant change of the effective radius of GJ3470b as a function of wavelength. This can be interpreted as a signature of scattering processes occurring in the planetary atmosphere, which should be cloud-free and with a low mean molecular weight. The unprecedented accuracy of our measurements demonstrates that the photometric detection of Earth-sized planets around M dwarfs is achievable using 8-10m size ground-based telescopes. We provide updated planetary parameters, and a greatly improved orbital ephemeris for any forthcoming study of this planet.Comment: 8 pages, 6 figures, 1 table; accepted for publication in A&

    Consumer confidence indicators and economic fluctuations in Nigeria

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    Consumer confidence indicators(CCI) serve as a veritable tool for providing useful information to policy makers, forecasters and the general public. Recent studies indicated the possibility of a slowdown in output, resulting from the pessimism of consumers in their expectations about the general state of the economy, even if their pessimism were not based on economic fundamentals. This study evaluated the predictive ability of the CCI in forecasting economic fluctuations in Nigeria. The study applied the Granger Causality tests, impulse response functions and forecast error variance decomposition to assess if CCI granger causes output growth as well as ascertain the magnitude of the change in GDP resulting from a change in CCI. Results from granger causality tests indicated a causal relationship between CCI indicators and real GDP growth in Nigeria. Furthermore, the study found that CCI explained the movements in economic activities, even though the magnitude was small. These results have important implications for the usefulness of CCI in planning and forecasting macroeconomic aggregates

    Antioxidant Activity of Extract From Ultrasonic-Assisted Extraction of Durian Peels

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    The increase in durian production results in the accumulation of durian peel waste. The bioactive component of durian peel has the potential to be used as an antioxidant. Thus, there is a need to carry out an extraction process to obtain bioactive compounds from durian peel. However, conventional extraction methods cause damage to phenolic compounds due to oxidation, hydrolysis and ionization reactions during the extraction process. Therefore, durian peel extraction was carried out using ultrasonic assisted extraction method (UAE) in this study. The purpose of this study was to investigate the effect of varying ratios of durian peel to ethanol solvents and extraction time on the yield, total phenolics content, total flavonoids content and antioxidant activity. The results of the research data were analyzed using a two-factor completely randomized design, which included variations of the ratio of durian peel to ethanol solvents and extraction time The Duncan's New Multiple Range Test (DNMRT) was carried out as a follow up test to determine the differences in each treatment at a significance level of 0.05. The results showed that the best treatment for peel extraction using ultrasonic assisted extraction was a 1: 9 ratio of durian peel to ethanol at an extraction time of 20 minutes. The extraction of durian peel under this condition gave the highest yield of 12.77 ± 0.16%, antioxidant activity (IC50) of 38.33 ± 0.12 ppm, total phenolic content of 63.30 ± 0.08 mgGAE / g and total flavonoids content of 47.53 ± 0.48 mgQE / g. In addition, total phenolics content and total flavonoid content showed a strong correlation to the antioxidant activity of durian peel extract

    Early clinical predictors and correlates of long-term morbidity in bipolar disorder

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    OBJECTIVES: Identifying factors predictive of long-term morbidity should improve clinical planning limiting disability and mortality associated with bipolar disorder (BD). METHODS: We analyzed factors associated with total, depressive and mania-related long-term morbidity and their ratio D/M, as %-time ill between a first-lifetime major affective episode and last follow-up of 207 BD subjects. Bivariate comparisons were followed by multivariable linear regression modeling. RESULTS: Total % of months ill during follow-up was greater in 96 BD-II (40.2%) than 111 BD-I subjects (28.4%; P=0.001). Time in depression averaged 26.1% in BD-II and 14.3% in BD-I, whereas mania-related morbidity was similar in both, averaging 13.9%. Their ratio D/M was 3.7-fold greater in BD-II than BD-I (5.74 vs. 1.96; P<0.0001). Predictive factors independently associated with total %-time ill were: [a] BD-II diagnosis, [b] longer prodrome from antecedents to first affective episode, and [c] any psychiatric comorbidity. Associated with %-time depressed were: [a] BD-II diagnosis, [b] any antecedent psychiatric syndrome, [c] psychiatric comorbidity, and [d] agitated/psychotic depressive first affective episode. Associated with %-time in mania-like illness were: [a] fewer years ill and [b] (hypo)manic first affective episode. The long-term D/M morbidity ratio was associated with: [a] anxious temperament, [b] depressive first episode, and [c] BD-II diagnosis. CONCLUSIONS: Long-term depressive greatly exceeded mania-like morbidity in BD patients. BD-II subjects spent 42% more time ill overall, with a 3.7-times greater D/M morbidity ratio, than BD-I. More time depressed was predicted by agitated/psychotic initial depressive episodes, psychiatric comorbidity, and BD-II diagnosis. Longer prodrome and any antecedent psychiatric syndrome were respectively associated with total and depressive morbidity
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