1,633 research outputs found
Resolved Mid-Infrared Emission Around AB Aur and V892 Tau with Adaptive Optics Nulling Interferometric Observations
We present the results of adaptive optics nulling interferometric
observations of two Herbig Ae stars, AB Aur and V892 Tau. Our observations at
10.3 microns show resolved circumstellar emission from both sources. Further
analysis of the AB Aur emission suggests that there is an inclined disk
surrounding the star. The diameter of the disk is derived to be 24 to 30 AU
with an inclination of 45 to 65 degrees from face-on, and a major-axis PA of 30
+/- 15 degrees (E of N). Differences in the physical characteristics between
the mid-IR emission and emission at other wavelengths (near-IR and millimeter),
found in previous studies, suggest a complex structure for AB Aur's
circumstellar environment, which may not be explained by a disk alone. The
similarity in the observed size of AB Aur's resolved emission and that of
another Herbig Ae star, HD 100546, is likely coincidental, as their respective
evolutionary states and spectral energy distributions suggest significantly
different circumstellar environments.Comment: 11 pages, 1 figure, Accepted for publication in ApJ Letter
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Systemic sclerosis is associated with specific alterations in gastrointestinal microbiota in two independent cohorts.
ObjectiveTo compare faecal microbial composition in patients with systemic sclerosis (SSc) from 2 independent cohorts with controls and to determine whether certain genera are associated with SSc-gastrointestinal tract (GIT) symptoms.DesignAdult patients with SSc from the University of California, Los Angeles (UCLA) and Oslo University Hospital (OUH) and healthy controls participated in this study (1:1:1). All participants provided stool specimens for 16S rRNA sequencing. Linear discriminant analysis effect size demonstrated genera with differential expression in SSc. Differential expression analysis for sequence count data identified specific genera associated with GIT symptoms as assessed by the GIT 2.0 questionnaire.ResultsThe UCLA-SSc and OUH-SSc cohorts were similar in age (52.1 and 60.5 years, respectively), disease duration (median (IQR): 6.6 (2.5-16.4) and 7.0 (1.0-19.2) years, respectively), gender distribution (88% and 71%, respectively), and GIT symptoms (mean (SD) total GIT 2.0 scores of 0.7 (0.6) and 0.6 (0.5), respectively). Principal coordinate analysis illustrated significant microbial community differences between SSc and controls (UCLA: p=0.001; OUH: p=0.002). Patients with SSc had significantly lower levels of commensal genera deemed to protect against inflammation, such as Bacteroides (UCLA and OUH), Faecalibacterium (UCLA), Clostridium (OUH); and significantly higher levels of pathobiont genera, such as Fusobacterium (UCLA), compared with controls. Increased abundance of Clostridium was associated with less severe GIT symptoms in both cohorts.ConclusionsThe present analysis detected specific aberrations in the lower GIT microbiota of patients with SSc from 2 geographically and ethnically distinct cohorts. These findings suggest that GIT dysbiosis may be a pathological feature of the SSc disease state
Allies Already Poised to Comply: How Social Proximity Affects Lactation-at-Work Law Compliance
This study demonstrates how legal compliance may be better achieved when organizations include individuals who will advocate for newly codified rights and related accommodations. To understand compliance with a new law and the rights it confers, this article examines as its case study the Lactation at Work law, which amends the Fair Labor Standards Act to mandate basic provisions for employees to express breast milk at work. In particular, this study interviewed those organizational actors who translate the law into the policies affecting workers\u27 daily lives: supervising mangers and human resources personnel. Those studied in this article were “Allies Already:” friends or relatives of breastfeeding workers, or ones themselves, who held pro‐breastfeeding values and understood the complexities of combining lactation and employment. They mobilized within their organization to comply with the law swiftly and fully—often even overcomplying. This article demonstrates how heightened compliance, particularly with new laws, may be achieved even without directly affected actors mobilizing their own rights if allies champion needed accommodations
Remotely sensed and modelled pasture biomass, land condition and the potential to improve grazing-management decision tools across the Australian rangelands
This report assesses the potential for expanding on current capacity to monitor land condition using remotely sensed fractional cover products to improve biomass estimation, animal productivity, pasture growth models and grazing decision tools (e.g. safe carrying capacity) across the Australian rangelands. We focus on northern Australia and include relevant research and implementation from southern Australia where appropriate
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Genome-wide association study for subclinical atherosclerosis in major arterial territories in the NHLBI's Framingham Heart Study
Introduction: Subclinical atherosclerosis (SCA) measures in multiple arterial beds are heritable phenotypes that are associated with increased incidence of cardiovascular disease. We conducted a genome-wide association study (GWAS) for SCA measurements in the community-based Framingham Heart Study. Methods: Over 100,000 single nucleotide polymorphisms (SNPs) were genotyped (Human 100K GeneChip, Affymetrix) in 1345 subjects from 310 families. We calculated sex-specific age-adjusted and multivariable-adjusted residuals in subjects tested for quantitative SCA phenotypes, including ankle-brachial index, coronary artery calcification and abdominal aortic calcification using multi-detector computed tomography, and carotid intimal medial thickness (IMT) using carotid ultrasonography. We evaluated associations of these phenotypes with 70,987 autosomal SNPs with minor allele frequency , call rate , and Hardy-Weinberg p-value in samples ranging from 673 to 984 subjects, using linear regression with generalized estimating equations (GEE) methodology and family-based association testing (FBAT). Variance components LOD scores were also calculated. Results: There was no association result meeting criteria for genome-wide significance, but our methods identified 11 SNPs with by GEE and five SNPs with by FBAT for multivariable-adjusted phenotypes. Among the associated variants were SNPs in or near genes that may be considered candidates for further study, such as for maximum internal carotid artery IMT and rs4814615 (FBAT p = 0.000003, located in PCSK2) for maximum common carotid artery IMT. Modest significant associations were noted with various SCA phenotypes for variants in previously reported atherosclerosis candidate genes, including NOS3 and ESR1. Associations were also noted of a region on chromosome 9p21 with CAC phenotypes that confirm associations with coronary heart disease and CAC in two recently reported genome-wide association studies. In linkage analyses, several regions of genome-wide linkage were noted, confirming previously reported linkage of internal carotid artery IMT on chromosome 12. All GEE, FBAT and linkage results are provided as an open-access results resource at http://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin\study.cgi?id=phs000007. Conclusion: The results from this GWAS generate hypotheses regarding several SNPs that may be associated with SCA phenotypes in multiple arterial beds. Given the number of tests conducted, subsequent independent replication in a staged approach is essential to identify genetic variants that may be implicated in atherosclerosis
Data abstractions for decision tree induction
AbstractWhen descriptions of data values in a database are too concrete or too detailed, the computational complexity needed to discover useful knowledge from the database will be generally increased. Furthermore, discovered knowledge tends to become complicated. A notion of data abstraction seems useful to resolve this kind of problems, as we obtain a smaller and more general database after the abstraction, from which we can quickly extract more abstract knowledge that is expected to be easier to understand. In general, however, since there exist several possible abstractions, we have to carefully select one according to which the original database is generalized. An inadequate selection would make the accuracy of extracted knowledge worse.From this point of view, we propose in this paper a method of selecting an appropriate abstraction from possible ones, assuming that our task is to construct a decision tree from a relational database. Suppose that, for each attribute in a relational database, we have a class of possible abstractions for the attribute values. As an appropriate abstraction for each attribute, we prefer an abstraction such that, even after the abstraction, the distribution of target classes necessary to perform our classification task can be preserved within an acceptable error range given by user.By the selected abstractions, the original database can be transformed into a small generalized database written in abstract values. Therefore, it would be expected that, from the generalized database, we can construct a decision tree whose size is much smaller than one constructed from the original database. Furthermore, such a size reduction can be justified under some theoretical assumptions. The appropriateness of abstraction is precisely defined in terms of the standard information theory. Therefore, we call our abstraction framework Information Theoretical Abstraction.We show some experimental results obtained by a system ITA that is an implementation of our abstraction method. From those results, it is verified that our method is very effective in reducing the size of detected decision tree without making classification errors so worse
Adaptive Optics Nulling Interferometric Constraints on the Mid-Infrared Exozodiacal Dust Emission around Vega
We present the results of mid-infrared nulling interferometric observations
of the main-sequence star alpha Lyr (Vega) using the 6.5 m MMT with its
adaptive secondary mirror. From the observations at 10.6 microns, we find that
there is no resolved emission from the circumstellar environment (at
separations greater than 0.8 AU) above 2.1% (3 sigma limit) of the level of the
stellar photospheric emission. Thus, we are able to place an upper limit on the
density of dust in the inner system of 650 times that of our own solar system's
zodiacal cloud. This limit is roughly 2.8 times better than those determined
with photometric excess observations such as those by IRAS. Comparison with
far-infrared observations by IRAS shows that the density of warm dust in the
inner system (< 30 AU) is significantly lower than cold dust at larger
separations. We consider two scenarios for grain removal, the sublimation of
ice grains and the presence of a planetary mass "sweeper." We find that if
sublimation of ice grains is the only removal process, a large fraction (> 80%)
of the material in the outer system is ice.Comment: 11 pages, 1 figure, Accepted to The Astrophysical Journal Letter
Ipl1/aurora kinase suppresses S-CDK-driven spindle formation during prophase I to ensure chromosome integrity during meiosis
Cells coordinate spindle formation with DNA repair and morphological modifications to chromosomes prior to their segregation to prevent cell division with damaged chromosomes. Here we uncover a novel and unexpected role for Aurora kinase in preventing the formation of spindles by Clb5-CDK (S-CDK) during meiotic prophase I and when the DDR is active in budding yeast. This is critical since S-CDK is essential for replication during premeiotic S-phase as well as double-strand break induction that facilitates meiotic recombination and, ultimately, chromosome segregation. Furthermore, we find that depletion of Cdc5 polo kinase activity delays spindle formation in DDR-arrested cells and that ectopic expression of Cdc5 in prophase I enhances spindle formation, when Ipl1 is depleted. Our findings establish a new paradigm for Aurora kinase function in both negative and positive regulation of spindle dynamics
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