11 research outputs found
Meaning and Grammar of Nouns and Verbs
The papers collected in this book cover contemporary and original research on semantic and grammatical issues of nouns and noun phrases, verbs and sentences, and aspects of the combination of nouns and verbs, in a great variety of languages. A special focus is put on noun types, tense and aspect semantics, granularity of verb meaning, and subcompositionality. The investigated languages and language groups include Austronesian, East Asian, Slavic, German, English, Hungarian and Lakhota. The collection provided in this book will be of interest to researchers and advanced students specialising in the fields of semantics, morphology, syntax, typology, and cognitive sciences
The Role of Galaxies and AGN in Reionising the IGM - I: Keck Spectroscopy of 5 < z < 7 Galaxies in the QSO Field J1148+5251
We introduce a new method for determining the influence of galaxies and
active galactic nuclei (AGN) on the physical state of the intergalactic medium
(IGM) at high redshift and illustrate its potential via a first application to
the field of the QSO J1148+5251. By correlating the spatial positions
of spectroscopically-confirmed Lyman break galaxies (LBGs) with fluctuations in
the Lyman alpha forest seen in the high signal-to-noise spectrum of a
background QSO, we provide a statistical measure of the typical escape fraction
of Lyman continuum photons close to the end of cosmic reionisation. Here we use
Keck DEIMOS spectroscopy to locate 7 colour-selected LBGs in the redshift range
and confirm a faint AGN. We then examine
the spatial correlation between this sample and Ly/Ly
transmission fluctuations in a Keck ESI spectrum of the QSO. Interpreting the
statistical HI proximity effect as arising from faint galaxies clustered around
the detected LBGs, we translate the observed mean Ly transmitted flux
around an average detected LBG into a constraint on the mean escape fraction
at . We also report evidence of
the individual transverse HI proximity effect of a luminous LBG via a
Ly transmission spike and two broad Ly transmission spikes
around the AGN. We discuss the possible origin of such associations
which suggest that while faint galaxies are primarily driving reionisation,
luminous galaxies and AGN may provide important contributions to the UV
background or thermal fluctuations of the IGM at . Although a limited
sample, our results demonstrate the potential of making progress using this
method in resolving one of the most challenging aspects of the contribution of
galaxies and AGN to cosmic reionisation.Comment: 21 pages, 16 figures, the version accepted in MNRA
The nature of high [O iii ]88 μ m/[C ii ]158 μm galaxies in the epoch of reionization: Low carbon abundance and a top-heavy IMF?
International audienceABSTRACT ALMA observations of z > 6 galaxies have revealed abnormally high [O iii]88 m/[C ii]158 m ratios and [C ii]158 m deficits compared to local galaxies. The origin of this behaviour is unknown. Numerous solutions have been proposed including differences in C and O abundance ratios, observational bias, and differences in ISM properties, including ionization parameter, gas density, or photodissociation region (PDR) covering fraction. In order to elucidate the underlying physics that drives this high-redshift phenomenon, we employ sphinx20, a state-of-the-art, cosmological radiation–hydrodynamics simulation, that resolves detailed ISM properties of thousands of galaxies in the epoch of reionization which has been post-processed with cloudy to predict emission lines. We find that the observed z > 6 [O iii]88 m–SFR and [C ii]158 m–SFR relations can only be reproduced when the C/O abundance ratio is ∼8 × lower than Solar and the total metal production is ∼4 × higher than that of a Kroupa IMF. This implies that high-redshift galaxies are potentially primarily enriched by low-metallicity core–collapse supernovae with a more top-heavy IMF. As AGB stars and type-Ia supernova begin to contribute to the galaxy metallicity, both the [C ii]158 m–SFR and [C ii]158 m luminosity functions are predicted to converge to observed values at z ∼ 4.5. While we demonstrate that ionization parameter, LyC escape fraction, ISM gas density, and CMB attenuation all drive galaxies towards higher [O iii]88 m/[C ii]158 m, observed values at z > 6 can only be reproduced with substantially lower C/O abundances compared to Solar. The combination of [C ii]158 m and [O iii]88 m can be used to predict the values of ionization parameter, ISM gas density, and LyC escape fraction and we provide estimates of these quantities for nine observed z > 6 galaxies. Finally, we demonstrate that [O i]63 m can be used as a replacement for [C ii]158  m in high-redshift galaxies where [C ii]158  m is unobserved and argue that more observation time should be used to target [O i]63 m at z > 6. Future simulations will be needed to self-consistently address the numerous uncertainties surrounding a varying IMF at high redshift and the associated metal returns
The Nature of High / Galaxies in the Epoch of Reionization: Low Carbon Abundance and a Top-Heavy IMF?
ALMA observations of galaxies have revealed abnormally high [OIII]/[CII] ratios and [CII] deficits compared to local galaxies. Numerous solutions have been proposed including differences in C and O abundance ratios, observational bias, and differences in ISM properties. In order to elucidate the underlying physics that drives this high-redshift phenomenon, we employ SPHINX, a state-of-the-art, cosmological radiation-hydrodynamics simulation, that resolves detailed ISM properties of thousands of galaxies in the epoch of reionization. We find that the observed [OIII]-SFR and [CII]-SFR relations can only be reproduced when the C/O abundance ratio is lower than Solar and the total metal production is higher than that of a Kroupa IMF. This implies that high-redshift galaxies are potentially primarily enriched by low-metallicity core-collapse supernovae with a more top-heavy IMF. As AGB stars and type-Ia supernova begin to contribute to the galaxy metallicity, both the [CII]-SFR and [CII] luminosity functions are predicted to converge to observed values at . While we demonstrate that ionisation parameter, LyC escape fraction, ISM gas density, and CMB attenuation all drive galaxies towards higher [OIII]/[CII], observed values at can only be reproduced with substantially lower C/O abundances compared to Solar. The combination of [CII] and [OIII] can be used to predict the values of ionisation parameter, ISM gas density, and LyC escape fraction and we provide estimates of these quantities for nine observed galaxies. Finally, we demonstrate that [OI] can be used as a replacement for [CII] in high-redshift galaxies where [CII] is unobserved and argue that more observation time should be used to target [OI] at . (Abridged
Detection of intramyocardially injected DiR-labeled mesenchymal stem cells by optical and optoacoustic tomography
The distribution of intramyocardially injected rabbit MSCs, labeled with the near-infrared dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbo-cyanine-iodide (DiR) using hybrid Fluorescence Molecular Tomography-X-ray Computed Tomography (FMT-XCT) and Multispectral Optoacoustic Tomography (MSOT) imaging technologies, was investigated. Viability and induction of apoptosis of DiR labeled MSCs were assessed by XTT-and Caspase-3/-7-testing in vitro. 2 x 10(6), 2 x 10(5) and 2 x 10(4) MSCs labeled with 5 and 10 mu g DiR/ml were injected into fresh frozen rabbit hearts. FMT-XCT, MSOT and fluorescence cryosection imaging were performed. Concentrations up to 10 mu g DiR/ml did not cause apoptosis in vitro (p > 0.05). FMT and MSOT imaging of labeled MSCs led to a strong signal. The imaging modalities highlighted a difference in cell distribution and concentration correlated to the number of injected cells. Ex-vivo cryosectioning confirmed the molecular fluorescence signal. FMT and MSOT are sensitive imaging techniques offering high-anatomic resolution in terms of detection and distribution of intramyocardially injected stem cells in a rabbit model. (C) 2017 The Authors. Published by Elsevier GmbH
Physical activity and dietary behaviour in a population-based sample of British 10-year old children: the SPEEDY study (Sport, Physical activity and Eating behaviour: Environmental Determinants in Young people)
Background The SPEEDY study was set up to quantify levels of physical activity (PA) and dietary habits and the association with potential correlates in 9–10 year old British school children. We present here the analyses of the PA, dietary and anthropometry data. Methods In a cross-sectional study of 2064 children (926 boys, 1138 girls) in Norfolk, England, we collected anthropometry data at school using standardised procedures. Body mass index (BMI) was used to define obesity status. PA was assessed with the Actigraph accelerometer over 7 days. A cut-off of = 2000 activity counts was used to define minutes of moderate-to-vigorous PA (MVPA). Dietary habits were assessed using the Health Behaviour in School Children food questionnaire. Weight status was defined using published international cut-offs (Cole, 2000). Differences between groups were assessed using independent t-tests for continuous data and chi-squared tests for categorical data. Results Valid PA data (>500 minutes per day on = 3 days) was available for 1888 children. Mean (± SD) activity counts per minute among boys and girls were 716.5 ± 220.2 and 635.6 ± 210.6, respectively (p < 0.001). Boys spent an average of 84.1 ± 25.9 minutes in MVPA per day compared to 66.1 ± 20.8 among girls (p < 0.001), with an average of 69.1% of children accumulating 60 minutes each day. The proportion of children classified as overweight and obese was 15.0% and 4.1% for boys and 19.3% and 6.6% for girls, respectively (p = 0.001). Daily consumption of at least one portion of fruit and of vegetables was 56.8% and 49.9% respectively, with higher daily consumption in girls than boys and in children from higher socioeconomic backgrounds. Conclusion Results indicate that almost 70% of children meet national PA guidelines, indicating that a prevention of decline, rather than increasing physical activity levels, might be an appropriate intervention target. Promotion of daily fruit and vegetable intake in this age group is also warranted, possibly focussing on children from lower socioeconomic backgrounds