2,449 research outputs found
Assessment of the quality of Gate area rainfall data from a Nimbus-5 radiometer
The quality of rainfall intensity estimates derived from passive microwave measurements by the electrically scanned microwave radiometer (ESMR-5) aboard the Nimbus 5 satellite are evaluated. The microwave measurements used are those coincident with the global atmospheric research program Atlantic tropical experiment (GATE). The ESMR 5 derived rainfall intensity estimates are compared with hourly averaged GATE radar rainfall measurements. It is determined from the transfer curves derived using the radar measurements as ground truth, that the ESMR 5 derived data consistently over estimates rainfall by a factor of approximately 1.4
Globular Cluster Formation in M82
We present high resolution mid-infrared (mid-IR; 11.7 and 17.65 micron) maps
of the central 400 pc region of the starburst galaxy M82. Seven star forming
clusters are identified which together provide ~ 15% of the total mid-IR
luminosity of the galaxy. Combining the mid-IR data with thermal radio
measurements and near- and mid-IR line emission, we find that these young
stellar clusters have inferred masses and sizes comparable to globular
clusters. At least 20% of the star formation in M82 is found to occur in
super-star clusters.Comment: 12 pages including three color figures; accepted for publication in
Ap
LANDSAT and environmental impact in the Paraiba Valley of Sao Paulo
There are no author-identified significant results in this report
Variations in Fe\u3csup\u3e3+\u3c/sup\u3e/∑Fe of Mariana Arc Basalts and Mantle Wedge \u3cem\u3ef\u3c/em\u3eO\u3csub\u3e2\u3c/sub\u3e
Arc basalts are more oxidized than mid-ocean ridge basalts, but it is unclear whether this difference is due to differentiation processes in the Earth’s crust or to a fundamental difference in the oxygen fugacity of their mantle sources. Distinguishing between these two hypotheses is important for understanding redox-sensitive processes related to arc magmatism, and thus more broadly how Earth materials cycle globally. We present major, volatile, and trace element concentrations in combination with Fe3+/∑Fe ratios determined in olivine-hosted glass inclusions and submarine glasses from five Mariana arc volcanoes and two regions of the Mariana Trough. For single eruptions, Fe3+/∑Fe ratios vary along liquid lines of descent that are either slightly oxidizing (olivine + clinopyroxene + plagioclase fractionation, CO2 ± H2O degassing) or reducing (olivine + clinopyroxene + plagioclase ± magnetite fractionation, CO2 + H2O + S degassing). Mariana samples are consistent with a global relationship between calc-alkaline affinity and both magmatic H2O and magmatic oxygen fugacity, where wetter, higher oxygen fugacity magmas display greater affinity for calc-alkaline differentiation. We find, however, that low-pressure differentiation cannot explain the majority of variations observed in Fe3+/∑Fe ratios for Mariana arc basalts, requiring primary differences in magmatic oxygen fugacity. Calculated oxygen fugacities of primary mantle melts at the pressures and temperatures of melt segregation are significantly oxidized relative to mid-ocean ridge basalts (∼QFM, where QFM is quartz–fayalite–magnetite buffer), ranging from QFM + 1·0 to QFM + 1·6 for Mariana arc basalts, whereas back-arc related samples record primary oxygen fugacities that range from QFM + 0·1 to QFM + 0·5. This Mariana arc sample suite includes a diversity of subduction influences, from lesser influence of a homogeneous H2O-rich component in the back-arc, to sediment melt- and fluid-dominated influences along the arc. Primary melt oxygen fugacity does not correlate significantly with sediment melt contributions (e.g. Th/La), nor can it be attributed to previous melt extraction in the back-arc. Primary melt oxygen fugacity correlates strongly with indices of slab fluids (e.g. Ba/La) from the Mariana Trough through the Mariana arc, increasing by 1·5 orders of magnitude as Ba/La increases by a factor of 10 relative to mid-ocean ridge basalts. These results suggest that contributions from the slab to the mantle wedge may be responsible for the elevated oxygen fugacity recorded by Mariana arc basalts and that slab fluids are potentially very oxidized
FGFR2 amplification in colorectal adenocarcinoma
FGFR2 is recurrently amplified in 5% of gastric cancers and 1%–4% of breast cancers; however, this molecular alteration has never been reported in a primary colorectal cancer specimen. Preclinical studies indicate that several FGFR tyrosine-kinase inhibitors (TKIs), such as AZD4547, have in vitro activity against the FGFR2-amplified colorectal cell line, NCI-H716. The efficacy of these inhibitors is currently under investigation in clinical trials for breast and gastric cancer. Thus, better characterizing colorectal tumors for FGFR2 amplification could identify a subset of patients who may benefit from FGFR TKI therapies. Here, we describe a novel FGFR2 amplification identified by clinical next-generation sequencing in a primary colorectal cancer. Further characterization of the tumor by immunohistochemistry showed neuroendocrine differentiation, similar to the reported properties of the NCI-H716 cell line. These findings demonstrate that the spectrum of potentially clinically actionable mutations detected by targeted clinical sequencing panels is not limited to only single-nucleotide polymorphisms and insertions/deletions but also to copy-number alterations.</jats:p
What are the participants’ perspectives of taking melatonin for the treatment of nocturia in Multiple Sclerosis? -a qualitative study embedded within a double blind RCT
Background: Multiple Sclerosis (MS) is a chronic neurological disorder caused by neurodegeneration within the central nervous system. It results in impaired physical, cognitive and psychological functioning and can also lead to lower urinary tract symptoms including nocturia. While clinical trials have suggested an association between nocturia and melatonin secretion, to our knowledge, no qualitative research has been conducted on the experience of taking melatonin to treat nocturia in progressive MS within a clinical trial. Methods: 17 semi-structured qualitative interviews were conducted as part of a double-blind, randomised, placebo controlled, crossover, clinical trial with consenting adults with MS. Interviews explored participants’ experiences of nocturia associated with MS and their experience of taking melatonin as a trial treatment for nocturia versus a placebo. Data was analysed using a thematic analysis. Results: Themes on the experience of nocturia revealed participants’ understandings of nocturia, the impact it had on their night and increased daily fatigue. Themes on the intervention showed perceived improvements to nocturia, sleep and energy and negative effects including lethargy, a lack of significant change and physical side effects including vivid dreams.Conclusion: This qualitative exploration revealed an association between nocturia and increased levels of fatigue during the day by those with MS. However, perspectives towards the effectiveness of melatonin as a potential treatment varied as both placebo and melatonin were perceived as having very similar effects
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Agonist-induced endocytosis of rat somatostatin receptor 1
Somatostatin-receptor 1 (sst1) is an autoreceptor in the central nervous system that regulates the release of somatostatin. Sst1 is present intracellularly and at the cell surface. To investigate sst1 trafficking, rat sst1 tagged with epitope was expressed in rat insulinoma cells 1046-38 (RIN-1046-38) and tracked by antibody labeling. Confocal microscopic analysis revealed colocalization of intracellularly localized rat sst1-human simplex virus (HSV) with Rab5a-green fluorescent protein and Rab11a-green fluorescent protein, indicating the distribution of the receptor in endocytotic and recycling organelles. Somatostatin-14 induced internalization of cell surface receptors and reduction of binding sites on the cell surface. It also stimulated recruitment of intracellular sst1-HSV to the plasma membrane. Confocal analysis of sst1-HSV revealed that the receptor was initially transported within superficial vesicles. Prolonged stimulation of the cells with the peptide agonist induced intracellular accumulation of somatostatin-14. Because the number of cell surface binding sites did not change during prolonged stimulation, somatostatin-14 was internalized through a dynamic process of continuous endocytosis, recycling, and recruitment of intracellularly present sst1-HSV. Accumulated somatostatin-14 bypassed degradation via the endosomal-lysosomal route and was instead rapidly released as intact and biologically active somatostatin-14. Our results show for the first time that sst1 mediates a dynamic process of endocytosis, recycling, and re-endocytosis of its cognate ligand
Oxygen isotopic ratios in cool R Coronae Borealis stars
We investigate the relationship between R Coronae Borealis (RCB) stars and
hydrogen-deficient carbon (HdC) stars by measuring precise 16O/18O ratios for
five cool RCB stars. The 16O/18O ratios are derived by spectrum synthesis from
high-resolution (R=50,000) K-band spectra. Lower limits to the 16O/17O and
14N/15}N ratios as well as Na and S abundances (when possible) are also given.
RCB stars in our sample generally display less 18O than HdC stars - the derived
16O/18O ratios range from 3 to 20. The only exception is the RCB star WX CrA,
which seems to be a HdC-like star with 16O/18O=0.3. Our result of a higher
16O/18O ratio for the RCB stars must be accounted for by a theory of the
formation and evolution of HdC and RCB stars. We speculate that a late
dredge-up of products of He-burning, principally 12C and 16O, may convert a
18O-rich HdC star into a 18O-poor RCB star as the H-deficient star begins its
final evolution from a cool supergiant to the top of the white dwarf cooling
track.Comment: Accepted for publication in the Astrophysical Journal; 21 pages, 3
Tables, 11 Figure
Observation of the Halo of NGC 3077 Near the "Garland" Region Using the Hubble Space Telescope
We report the detection of upper main sequence stars and red giant branch
stars in the halo of an amorphous galaxy, NGC3077. The observations were made
using Wide Field Planetary Camera~2 on board the Hubble Space Telescope. The
red giant branch luminosity function in I-band shows a sudden discontinuity at
I = 24.0 +- 0.1 mag. Identifying this with the tip of the red giant branch
(TRGB), and adopting the calibration provided by Lee, Freedman, & Madore (1993)
and the foreground extinction of A_B = 0.21 mag, we obtain a distance modulus
of (m-M)_0 = 27.93 +- 0.14(random) +- 0.16(sys). This value agrees well with
the distance estimates of four other galaxies in the M81 Group. In addition to
the RGB stars, we observe a concentration of upper main sequence stars in the
halo of NGC3077, which coincides partially with a feature known as the
``Garland''. Using Padua isochrones, these stars are estimated to be <150 Myrs
old. Assuming that the nearest encounter between NGC3077 and M81 occurred 280
Myrs ago as predicted by the numerical simulations (Yun 1997), the observed
upper main sequence stars are likely the results of the star formation
triggered by the M81-NGC3077 tidal interaction.Comment: 15 pages, 8 figures. Accepted for publication in Astrophysical
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