421 research outputs found
Recovering the properties of high redshift galaxies with different JWST broad-band filters
Imaging with the James Webb Space Telescope (JWST) will allow for observing
the bulk of distant galaxies at the epoch of reionisation. The recovery of
their properties, such as age, color excess E(B-V), specific star formation
rate (sSFR) and stellar mass, will mostly rely on spectral energy distribution
fitting, based on the data provided by JWST's two imager cameras, namely the
Near Infrared Camera (NIRCam) and the Mid Infrared Imager (MIRI). In this work
we analyze the effect of choosing different combinations of NIRCam and MIRI
broad-band filters, from 0.6 {\mu}m to 7.7 {\mu}m, on the recovery of these
galaxy properties. We performed our tests on a sample of 1542 simulated
galaxies, with known input properties, at z=7-10. We found that, with only 8
NIRCam broad-bands, we can recover the galaxy age within 0.1 Gyr and the color
excess within 0.06 mag for 70% of the galaxies. Besides, the stellar masses and
sSFR are recovered within 0.2 and 0.3 dex, respectively, at z=7-9. Instead, at
z=10, no NIRCam band traces purely the {\lambda}> 4000 {\AA} regime and the
percentage of outliers in stellar mass (sSFR) increases by > 20% (> 90%), in
comparison to z=9. The MIRI F560W and F770W bands are crucial to improve the
stellar mass and the sSFR estimation at z=10. When nebular emission lines are
present, deriving correct galaxy properties is challenging, at any redshift and
with any band combination. In particular, the stellar mass is systematically
overestimated in up to 0.3 dex on average with NIRCam data alone and including
MIRI observations improves only marginally the estimation.Comment: 21 pages, 11 figures, 4 tables. Accepted for publication at the ApJ
Observations of the Hubble Deep Field with the Infrared Space Observatory. I. Data reduction, maps and sky coverage
We present deep imaging at 6.7 micron and 15 micron from the CAM instrument
on the Infrared Space Observatory (ISO), centred on the Hubble Deep Field
(HDF). These are the deepest integrations published to date at these
wavelengths in any region of sky. We discuss the observation strategy and the
data reduction. The observed source density appears to approach the CAM
confusion limit at 15 micron, and fluctuations in the 6.7 micron sky background
may be identifiable with similar spatial fluctuations in the HDF galaxy counts.
ISO appears to be detecting comparable field galaxy populations to the HDF, and
our data yields strong evidence that future IR missions (such as SIRTF, FIRST
and WIRE) as well as SCUBA and millimetre arrays will easily detect field
galaxies out to comparably high redshifts.Comment: 7 pages, LaTeX (using mn.sty), 9 figures included as GIFs. Gzipped
Postscipt version available from http://artemis.ph.ic.ac.uk/hdf/papers/ps/.
Further information on ISO-HDF project can be found at
http://artemis.ph.ic.ac.uk/hdf
COVID-19 restrictions and fathers of infants in neonatal care.
This is a letter without an abstract
Observations of the Hubble Deep Field with the Infrared Space Observatory V. Spectral energy distributions starburst models and star formation history
We have modelled the spectral energy distributions of the 13 Hubble Deep Field (HDF) galaxies reliably detected by the Infrared Space Observatoiy (ISO). For two galaxies the emission detected by ISO is consistent with being starlight or the infrared 'cirrus' in the galaxies. For the remaining 11 galaxies there is a clear mid-infrared excess, which we interpret as emission from dust associated with a strong starburst. 10 of these galaxies are spirals or interacting pairs, while the remaining one is an elliptical with a prominent nucleus and broad emission lines. We give a new discussion of how the star formation rate can be deduced from the far-infrared luminosity, and derive star formation rates for these galaxies of 8-1000ø M¿ yr-1, where ø takes account of the uncertainty in the initial mass function. The HDF galaxies detected by ISO are clearly forming stars at a prodigious rate compared with nearby normal galaxies. We discuss the implications of our detections for the history of star and heavy element formation in the Universe. Although uncertainties in the calibration, reliability of source detection, associations and starburst models remain, it is clear that dust plays an important role in star formation out to redshift 1 at least
Towards integration of research and monitoring at forest ecosystems in Europe
Aim of study: The main aim of the work was to summarize availability, quality and comparability of on-going European Research and Monitoring Networks (ERMN), based on the results of a COST FP0903 Action questionnaire carried out in September 2010 and May 2012. Area of study: The COST Action FP0903 involves 29 European countries and 4 non-COST institutions from USA, Morocco and Tunisia. In this study, the total of 22 replies to the questionnaire from 18 countries were included. Materials and methods: Based on the feedback from the Action FP0903 countries, the most popular European Networks were identified. Thereafter, the access to the network database, available quality assurance/quality control procedures and publication were described. Finally, the so-called “Supersites” concept, defined as a “highly instrumented research infrastructure, for both research and monitoring of soil-plant-atmosphere interactions” was discussed. Main results: The result of the survey indicate that the vast majority of the Action FP0903 countries participate in the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forest (ICP Forest). The multi-disciplinary International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems (ICPIM) is the second most widespread forest programme. Research highlights: To fully understand biochemical cycles in forest ecosystems, long-term monitoring is needed. Hence, a network of “Supersites”, is proposed. The application of the above infrastructure can be an effective way to attain a better integration of research and monitoring networks at forest sites in Europ
Inactivation of the transforming growth factor β type II receptor in human small cell lung cancer cell lines
Transforming growth factor β (TGF-β) exerts a growth inhibitory effect on many cell types through binding to two types of receptors, the type I and II receptors. Resistance to TGF-β due to lack of type II receptor (RII) has been described in some cancer types including small cell lung cancer (SCLC). The purpose of this study was to examine the cause of absent RII expression in SCLC cell lines. Northern blot analysis showed that RII RNA expression was very weak in 16 of 21 cell lines. To investigate if the absence of RII transcript was due to mutations, we screened the poly-A tract for mutations, but no mutations were detected. Additional screening for mutations of the RII gene revealed a GG to TT base substitution in one cell line, which did not express RII. This mutation generates a stop codon resulting in predicted synthesis of a truncated RII of 219 amino acids. The nature of the mutation, which has not previously been observed in RII, has been linked to exposure to benzo[a]-pyrene, a component of cigarette smoke. Since RII has been mapped to chromosome 3p22 and nearby loci are often hypermethylated in SCLC, it was examined whether the lack of RII expression was due to hypermethylation. Southern blot analysis of the RII promoter did not show altered methylation patterns. The restriction endonuclease pattern of the RII gene was altered in two SCLC cell lines when digested with Sma 1. However, treatment with 5-aza-2′-deoxycytidine did not induce expression of RII mRNA. Our results indicate that in SCLC lack of RII mRNA is not commonly due to mutations and inactivation of RII transcription was not due to hypermethylation of the RII promoter or gene. Thus, these data show that in most cases of the SCLC cell lines, the RII gene and promoter is intact in spite of absent RII expression. However, the nature of the mutation found could suggest that it was caused by cigarette smoking. © 1999 Cancer Research Campaig
A randomized study of the effect of fish oil on n-3 fatty acid incorporation and nutritional status in lung cancer patients
Maternal exposure to UV filters:Associations with maternal thyroid hormones, IGF-I/IGFBP3 and birth outcomes
Background: Several chemical UV filters/absorbers ('UV filters' hereafter) have endocrine-disrupting properties in vitro and in vivo. Exposure to these chemicals, especially during prenatal development, is of concern.
Objectives: To examine maternal exposure to UV filters, associations with maternal thyroid hormone, with growth factor concentrations as well as to birth outcomes.
Methods: Prospective study of 183 pregnant women with 2nd trimester serum and urine samples available. Maternal concentrations of the chemical UV filters benzophenone-1 (BP-1) and benzophenone-3 (BP-3) in urine and 4-hydroxy-benzophenone (4-HBP) in serum were measured by liquid chromatography–tandem mass spectrometry
(LC–MS/MS). The relationships between 2nd trimester maternal concentrations of the three chemical UV filters and maternal serum concentrations of thyroid hormones and growth factors, as well as birth outcomes (weight, height, and head and abdominal circumferences) were examined.
Results: Positive associations between maternal serum concentrations of 4-HBP and triiodothyronine (T3), thyroxine (T4), insulin-like growth factor I (IGF-I) and its binding protein IGFBP3 were observed in mothers carrying male fetuses. Male infants of mothers in the middle 4-HBP exposure group had statistically significantly lower weight and shorter head and abdominal circumferences at birth compared to the low exposure group.
Conclusions: Widespread exposure of pregnant women to chemical UV filters and the possible impact on maternal thyroid hormones and growth factors, and on fetal growth, calls for further studies on possible long-term consequences of the exposure to UV filters on fetal development and children’s health
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