76 research outputs found
Comparative Evolution of Jupiter and Saturn
We present evolutionary sequences for Jupiter and Saturn, based on new
nongray model atmospheres, which take into account the evolution of the solar
luminosity and partitioning of dense components to deeper layers. The results
are used to set limits on the extent to which possible interior phase
separation of hydrogen and helium may have progressed in the two planets. When
combined with static models constrained by the gravity field, our evolutionary
calculations constrain the helium mass fraction in Jupiter to be between 0.20
and 0.27, relative to total hydrogen and helium. This is in agreement with the
Galileo determination. The helium mass fraction in Saturn's atmosphere lies
between 0.11 and 0.25, higher than the Voyager determination. Based on the
discrepancy between the Galileo and Voyager results for Jupiter, and our
models, we predict that Cassini measurements will yield a higher atmospheric
helium mass fraction for Saturn relative to the Voyager value.Comment: 18 pages, LaTeX, 4 figures. submitted to ``Planetary and Space
Science.'
Theortetical Models of Extrasolar Giant Planets
The recent discoveries of giant planets around nearby stars have galvanized
the planetary science community, astronomers, and the public at large. Since
{\it direct} detection is now feasible, and is suggested by the recent
acquisition of Gl229 B, it is crucial for the future of extrasolar planet
searches that the fluxes, evolution, and physical structure of objects from
Saturn's mass to 15 Juipter masses be theoretically investigated. We discuss
our first attempts to explore the characteristics of extrasolar giant planets
(EGPs), in aid of both NASA's and ESA's recent plans to search for such planets
around nearby stars.Comment: LaTeX, using espcrc2.sty style files from Elsevier, 10 pages, 4
figures, to be published in the Proceedings of the International Conference
on "Sources and Detection of Dark Matter in the Universe," ed. by D. Sanders
et al. (Nuclear Physics B Supplement), 199
The BIG protein distinguishes the process of CO2 -induced stomatal closure from the inhibition of stomatal opening by CO2
We conducted an infrared thermal imaging-based genetic screen to identify Arabidopsis mutants displaying aberrant stomatal behavior in response to elevated concentrations of CO2 . This approach resulted in the isolation of a novel allele of the Arabidopsis BIG locus (At3g02260) that we have called CO2 insensitive 1 (cis1). BIG mutants are compromised in elevated CO2 -induced stomatal closure and bicarbonate activation of S-type anion channel currents. In contrast with the wild-type, they fail to exhibit reductions in stomatal density and index when grown in elevated CO2 . However, like the wild-type, BIG mutants display inhibition of stomatal opening when exposed to elevated CO2 . BIG mutants also display wild-type stomatal aperture responses to the closure-inducing stimulus abscisic acid (ABA). Our results indicate that BIG is a signaling component involved in the elevated CO2 -mediated control of stomatal development. In the control of stomatal aperture by CO2 , BIG is only required in elevated CO2 -induced closure and not in the inhibition of stomatal opening by this environmental signal. These data show that, at the molecular level, the CO2 -mediated inhibition of opening and promotion of stomatal closure signaling pathways are separable and BIG represents a distinguishing element in these two CO2 -mediated responses
Juno spacecraft measurements of Jupiter's gravity imply a dilute core
Stars and planetary system
The Theory of Brown Dwarfs and Extrasolar Giant Planets
Straddling the traditional realms of the planets and the stars, objects below
the edge of the main sequence have such unique properties, and are being
discovered in such quantities, that one can rightly claim that a new field at
the interface of planetary science and and astronomy is being born. In this
review, we explore the essential elements of the theory of brown dwarfs and
giant planets, as well as of the new spectroscopic classes L and T. To this
end, we describe their evolution, spectra, atmospheric compositions, chemistry,
physics, and nuclear phases and explain the basic systematics of
substellar-mass objects across three orders of magnitude in both mass and age
and a factor of 30 in effective temperature. Moreover, we discuss the
distinctive features of those extrasolar giant planets that are irradiated by a
central primary, in particular their reflection spectra, albedos, and transits.
Aspects of the latest theory of Jupiter and Saturn are also presented.
Throughout, we highlight the effects of condensates, clouds, molecular
abundances, and molecular/atomic opacities in brown dwarf and giant planet
atmospheres and summarize the resulting spectral diagnostics. Where possible,
the theory is put in its current observational context.Comment: 67 pages (including 36 figures), RMP RevTeX LaTeX, accepted for
publication in the Reviews of Modern Physics. 30 figures are color. Most of
the figures are in GIF format to reduce the overall size. The full version
with figures can also be found at:
http://jupiter.as.arizona.edu/~burrows/papers/rm
Overlap of Genetic Risk between Interstitial Lung Abnormalities and Idiopathic Pulmonary Fibrosis
Rationale: Interstitial lung abnormalities (ILAs) are associated with the highest genetic risk locus for idiopathic pulmonary fibrosis (IPF); however, the extent to which there are unique associations among individuals with ILAs or additional overlap with IPF is not known.Objectives: To perform a genome-wide association study (GWAS) of ILAs.Methods: ILAs and a subpleural-predominant subtype were assessed on chest computed tomography (CT) scans in the AGES (Age Gene/Environment Susceptibility), COPDGene (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease [COPD]), Framingham Heart, ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points), MESA (Multi-Ethnic Study of Atherosclerosis), and SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study) studies. We performed a GWAS of ILAs in each cohort and combined the results using a meta-analysis. We assessed for overlapping associations in independent GWASs of IPF.Measurements and Main Results: Genome-wide genotyping data were available for 1,699 individuals with ILAs and 10,274 control subjects. The MUC5B (mucin 5B) promoter variant rs35705950 was significantly associated with both ILAs (P = 2.6 Ă— 10-27) and subpleural ILAs (P = 1.6 Ă— 10-29). We discovered novel genome-wide associations near IPO11 (rs6886640, P = 3.8 Ă— 10-8) and FCF1P3 (rs73199442, P = 4.8 Ă— 10-8) with ILAs, and near HTRE1 (rs7744971, P = 4.2 Ă— 10-8) with subpleural-predominant ILAs. These novel associations were not associated with IPF. Among 12 previously reported IPF GWAS loci, five (DPP9, DSP, FAM13A, IVD, and MUC5B) were significantly associated (P < 0.05/12) with ILAs.Conclusions: In a GWAS of ILAs in six studies, we confirmed the association with a MUC5B promoter variant and found strong evidence for an effect of previously described IPF loci; however, novel ILA associations were not associated with IPF. These findings highlight common genetically driven biologic pathways between ILAs and IPF, and also suggest distinct ones
Thermal Evolution and Magnetic Field Generation in Terrestrial Planets and Satellites
Whole-genome sequencing of chronic lymphocytic leukemia identifies subgroups with distinct biological and clinical features
The value of genome-wide over targeted driver analyses for predicting clinical outcomes of cancer patients is debated. Here, we report the whole-genome sequencing of 485 chronic lymphocytic leukemia patients enrolled in clinical trials as part of the United Kingdom’s 100,000 Genomes Project. We identify an extended catalog of recurrent coding and noncoding genetic mutations that represents a source for future studies and provide the most complete high-resolution map of structural variants, copy number changes and global genome features including telomere length, mutational signatures and genomic complexity. We demonstrate the relationship of these features with clinical outcome and show that integration of 186 distinct recurrent genomic alterations defines five genomic subgroups that associate with response to therapy, refining conventional outcome prediction. While requiring independent validation, our findings highlight the potential of whole-genome sequencing to inform future risk stratification in chronic lymphocytic leukemia
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