407,109 research outputs found
Chemical Enrichment RGS cluster sample (CHEERS): Constraints on turbulence
Feedback from AGN, galactic mergers, and sloshing are thought to give rise to
turbulence, which may prevent cooling in clusters. We aim to measure the
turbulence in clusters of galaxies and compare the measurements to some of
their structural and evolutionary properties. It is possible to measure the
turbulence of the hot gas in clusters by estimating the velocity widths of
their X-ray emission lines. The RGS Spectrometers aboard XMM-Newton are
currently the only instruments provided with sufficient effective area and
spectral resolution in this energy domain. We benefited from excellent 1.6Ms
new data provided by the CHEERS project. The new observations improve the
quality of the archival data and allow us to place constraints for some
clusters, which were not accessible in previous work. One-half of the sample
shows upper limits on turbulence less than 500km/s. For several sources, our
data are consistent with relatively strong turbulence with upper limits on the
velocity widths that are larger than 1000km/s. The NGC507 group of galaxies
shows transonic velocities, which are most likely associated with the merging
phenomena and bulk motions occurring in this object. Where both low- and
high-ionization emission lines have good enough statistics, we find larger
upper limits for the hot gas, which is partly due to the different spatial
extents of the hot and cool gas phases. Our upper limits are larger than the
Mach numbers required to balance cooling, suggesting that dissipation of
turbulence may prevent cooling, although other heating processes could be
dominant. The systematics associated with the spatial profile of the source
continuum make this technique very challenging, though still powerful, for
current instruments. The ASTRO-H and Athena missions will revolutionize the
velocity estimates and discriminate between different spatial regions and
temperature phases.Comment: 16 pages, 18 figures, 3 tables, accepted for publications in
Astronomy and Astrophysic
Minimal Information About Sample Preparation for Phosphoproteomics
This guideline describes parameters and conditions involved in phosphopeptide sample preparation. It covers from the description and preparation of the cells and tissues to the fractionation and specific enrichment of phosphopeptides for MS analysis. The guideline is prepared in order to easily cope with many of the experimental designs used in phosphoproteomic studies. 
 
The document is subdivided as follows:
1. General features
2. Sample processing
3. Protein Purification/Fractionation
4. Peptide Purification/Fractionation
5. Phosphopeptide enrichment

Developing Mathematics Enrichment Workshops for Middle School Students: Philosophy and Sample Workshops
This paper describes our approach to organizing enrichment activities using advanced mathematics topics for diverse audiences of middle school students. We discuss our philosophy and approaches for the structure of these workshops, and then provide sample schedules and resource materials. The workshops cover activities on the following topics: Graphing Calculators; The Chaos Game; Statistical Sampling; CT Scans–the reconstruction problem; The Platonic and Archimedean solids; The Shape of Space; Symmetry; The Binary Number System and the game of NIM; Graph Theory: Proof by Counterexample
Metal Abundances in the Cool-Cores of Galaxy Clusters
We use XMM-Newton data to carry out a detailed study of the Si, Fe and Ni
abundances in the cool cores of a representative sample of 26 local clusters.
We have performed a careful evaluation of the systematic uncertainties related
to the instruments, the plasma codes and the spectral modeling finding that the
major source of uncertainty is in the plasma codes. Our Si, Fe, Ni, Si/Fe and
Ni/Fe distributions feature only moderate spreads (from 20% to 30%) around
their mean values strongly suggesting similar enrichment processes at work in
all our cluster cores. Our sample averaged Si/Fe ratio is comparable to those
measured in samples of groups and high luminosity ellipticals implying that the
enrichment process in ellipticals, dominant galaxies in groups and BCGs in
clusters is quite similar. Although our Si/Fe and Ni/Fe abundance ratios are
fairly well constrained, the large uncertainties in the supernovae yields
prevent us from making a firm assessment of the relative contribution of type
Ia and core-collapsed supernovae to the enrichment process. All that can really
be said with some certainty is that both contribute to the enrichment of
cluster cores.Comment: 14 pages, accepted for publication in Astronomy and Astrophysic
Recommended from our members
Dual isotopic composition of methane in Murchison meteorite
Dual isotopic composition (H and C) of methane extracted from a small sample of Murchison meteorite reveals a deuterium enrichment for this molecule, indicating the presence of interstellar hydrogen
Thermal Conductivity of Isotopically Enriched 28Si Revisited
The thermal conductivity of isotopically enriched 28Si (enrichment better
than 99.9%) was redetermined independently in three laboratories by high
precision experiments on a total of 4 samples of different shape and degree of
isotope enrichment in the range from 5 to 300 K with particular emphasis on the
range near room temperature. The results obtained in the different laboratories
are in good agreement with each other. They indicate that at room temperature
the thermal conductivity of isotopically enriched 28Si exceeds the thermal
conductivity of Si with a natural, unmodified isotope mixture by 102 %.
This finding is in disagreement with an earlier report by Ruf et al. At
26 K the thermal conductivity of 28Si reaches a maximum. The maximum
value depends on sample shape and the degree of isotope enrichment and exceeds
the thermal conductivity of natural Si by a factor of 8 for a 99.982%
28Si enriched sample. The thermal conductivity of Si with natural isotope
composition is consistently found to be 3% lower than the values
recommended in the literature
The Penn State - Torun Centre for Astronomy Planet Search stars. II. Lithium abundance analysis of the Red Giant Clump sample
Using the sample of 348 stars from the PennState-Torun Centre for Astronomy
Planet Search, for which uniformly determined atmospheric parameters are
available, with chemical abundances and rotational velocities presented here,
we investigate various channels of Li enrichment in giants. Our work is based
on the HET/HRS spectra. The A(Li) was determined from the 670.8nm line, while
we use a more extended set of lines for alpha-elements abundances. In a series
of K-S tests, we compare Li-rich giants with other stars in the sample. We also
use available IR photometric and kinematical data in search for evidence of
mass-loss. We investigate properties of the most Li-abundant giants in more
detail by using multi-epoch precise radial velocities. We present Li and
alpha-elements abundances, as well as vsini for 348 stars. We detected Li in 92
stars, of which 82 are giants. 11 of them show significant Li abundance
A(Li)>1.4 and 7 of them are Li-overabundant objects, according to criterion of
A(Li)>1.5 and their location on HR diagram, including two giants with Li
abundances close to meteoritic level. For another 271 stars, upper limits of
A(Li) are presented. We show that Li-rich giants are among the most massive
stars from our sample and show larger than average effective temperatures. They
are indistinguishable from the complete sample in terms of their distribution
of luminosity, [Fe/H], vsini, and alpha-elements abundances. Our results do not
point out to one specific Li enrichment mechanism operating in our sample of
giants. On the contrary, in some cases, we cannot identify fingerprints of any
of known scenarios. We show, however, that the 4 most Li-rich giant in our
sample either have low-mass companions or have RV variations at the level of
~100 m/s, which strongly suggests that the presence of companions is an
important factor in the Li-enrichment processes in giants.Comment: Accepted for publication in A&A, 13 figures, 11 tables, 26 page
Program for Education and Enrichment of Relational Skills: Parental Outcomes with an ADHD Sample
The goal of the current study was to examine the effect of PEERS®, a 14-week parent-assisted friendship-building program for adolescents with ADHD, on parental functioning, quality of the parent-adolescent relationship, and family functioning. Participants included 25 parents (19 mothers, 6 fathers) of adolescents with ADHD. Families completed the Program for the Education and Enrichment of Relational Skills (PEERS®; Laugeson & Frankel, 2010). Measures of parenting stress, parental efficacy, parent-adolescent communication, parent-adolescent involvement, causal attributions for negative social interactions, and family chaos were completed by parents at pre and post-treatment. Parents demonstrated statistically significant improvements in parenting stress and parent-adolescent communication and marginally statistically significant improvement in parental efficacy. Parents also demonstrated statistically reliable change in measures of parenting stress, parent-adolescent communication, parent-adolescent involvement, and family chaos. Overall, these findings demonstrate the benefit of PEERS® at improving parental functioning, quality of the parent-adolescent relationship, and family functioning for families of adolescents with ADHD
Whole-blood sorting, enrichment and in situ immunolabeling of cellular subsets using acoustic microstreaming
Analyzing undiluted whole human blood is a challenge due to its complex composition of hematopoietic cellular populations, nucleic acids, metabolites, and proteins. We present a novel multi-functional microfluidic acoustic streaming platform that enables sorting, enrichment and in situ identification of cellular subsets from whole blood. This single device platform, based on lateral cavity acoustic transducers (LCAT), enables (1) the sorting of undiluted donor whole blood into its cellular subsets (platelets, RBCs, and WBCs), (2) the enrichment and retrieval of breast cancer cells (MCF-7) spiked in donor whole blood at rare cell relevant concentrations (10 mL− 1), and (3) on-chip immunofluorescent labeling for the detection of specific target cellular populations by their known marker expression patterns. Our approach thus demonstrates a compact system that integrates upstream sample processing with downstream separation/enrichment, to carry out multi-parametric cell analysis for blood-based diagnosis and liquid biopsy blood sampling
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