2,027 research outputs found
KITD816V+ systemic mastocytosis associated with KITD816V+ acute erythroid leukaemia: first case report with molecular evidence for same progenitor cell derivation
Toll-like receptor (TLR)-9 recognizes CpG motifs in microbial DNA. TLR9 signalling stimulates innate antimicrobial immunity and modulates adaptive immune responses including autoimmunity against chromatin, e.g., in systemic lupus erythematosus (SLE). This review summarizes the available data for a role of TLR9 signalling in lupus and discusses the following questions that arise from these observations: 1) Is CpG-DNA/TLR9 interaction involved in infection-induced disease activity of lupus? 2) What are the risks of CpG motifs in vaccine adjuvants for lupus patients? 3) Is TLR9 signalling involved in the pathogenesis of lupus by recognizing self DNA
Signatures of Dark Matter Scattering Inelastically Off Nuclei
Direct dark matter detection focuses on elastic scattering of dark matter
particles off nuclei. In this study, we explore inelastic scattering where the
nucleus is excited to a low-lying state of 10-100 keV, with subsequent prompt
de-excitation. We calculate the inelastic structure factors for the odd-mass
xenon isotopes based on state-of-the-art large-scale shell-model calculations
with chiral effective field theory WIMP-nucleon currents. For these cases, we
find that the inelastic channel is comparable to or can dominate the elastic
channel for momentum transfers around 150 MeV. We calculate the inelastic
recoil spectra in the standard halo model, compare these to the elastic case,
and discuss the expected signatures in a xenon detector, along with
implications for existing and future experiments. The combined information from
elastic and inelastic scattering will allow to determine the dominant
interaction channel within one experiment. In addition, the two channels probe
different regions of the dark matter velocity distribution and can provide
insight into the dark halo structure. The allowed recoil energy domain and the
recoil energy at which the integrated inelastic rates start to dominate the
elastic channel depend on the mass of the dark matter particle, thus providing
a potential handle to constrain its mass.Comment: 9 pages, 7 figures. Matches resubmitted version to Phys. Rev. D. One
figure added; supplemental material (fits to the structure functions) added
as an Appendi
The Influence of Drawing on Third Graders\u27 Writing Performance
This study compared the writing products of 60 third grade students who drew before writing a story on a self-selected topic (Experimental Group) with the writing products of 59 third grade students who simply wrote without drawing (Control Group). An analysis of the students\u27 writing products revealed two important findings. First, students who drew be fore writing tended to produce more words, more sentences, and more idea units, and their overall writing performance was higher than the students who wrote without drawing. Second, these results were consistent for boys and girls regardless of group membership. The findings indicate that the differences in writing performance were probably due to the integration of drawing and writing. Implications for writing research and instruction are discussed
Revising the Metacognitive Awareness of Reading Strategies Inventory (MARSI) and Testing for Factorial Invariance
In this study, we revised the Metacognitive Awareness of Reading Strategies Inventory (MARSI), a self-report instrument designed to assess students’ awareness of reading strategies when reading school-related materials. We collected evidence of structural, generalizability, and external aspects of validity for the revised inventory (MARSI-R). We first conducted a confirmatory factor analysis of the MARSI instrument, which resulted in the reduction of the number of strategy statements from 30 to 15. We then tested MARSI-R for factorial invariance across gender and ethnic groups and found that there is a uniformity in student interpretation of the reading strategy statements across these groups, thus allowing for their comparison on levels of metacognitive processing skills. We found evidence of the external validity aspect of MARSI-R data through correlations of such data with a measure of the students’ perceived reading ability. Given that this journal is oriented to second language learning and teaching, our article also includes comments on the Survey of Reading Strategies (SORS), which was based on the original MARSI and was designed to assess adolescents’ and adults’ metacognitive awareness and perceived use of ESL reading strategies. We provide a copy of the MARSI-R instrument and discuss the implications of the study’s findings in light of new and emerging insights relative to assessing students’ metacognitive awareness and perceived use of reading strategies
Revising the Metacognitive Awareness of Reading Strategies Inventory (MARSI) and testing for factorial invariance
In this study, we revised the Metacognitive Awareness of Reading Strategies Inventory (MARSI), a self-report instrument designed to assess students’ awareness of reading strategies when reading school-related materials. We collected evidence of structural, generalizability, and external aspects of validity for the revised inventory (MARSI-R). We first conducted a confirmatory factor analysis of the MARSI instrument, which resulted in the reduction of the number of strategy statements from 30 to 15. We then tested MARSI-R for factorial invariance across gender and ethnic groups and found that there is a uniformity in student interpretation of the reading strategy statements across these groups, thus allowing for their comparison on levels of metacognitive processing skills. We found evidence of the external validity aspect of MARSI-R data through correlations of such data with a measure of the students’ perceived reading ability. Given that this journal is oriented to second language learning and teaching, our article also includes comments on the Survey of Reading Strategies (SORS), which was based on the original MARSI and was designed to assess adolescents’ and adults’ metacognitive awareness and perceived use of ESL reading strategies. We provide a copy of the MARSI-R instrument and discuss the implications of the study’s findings in light of new and emerging insights relative to assessing students’ metacognitive awareness and perceived use of reading strategies
The Lopsidedness of Present-Day Galaxies: Results from the Sloan Digital Sky Survey
Large-scale asymmetries in the stellar mass distribution in galaxies are
believed to trace non-equilibrium situations in the luminous and/or dark matter
component. These may arise in the aftermath of events like mergers, accretion,
and tidal interactions. These events are key in the evolution of galaxies. In
this paper we quantify the large-scale lopsidedness of light distributions in
25155 galaxies at z < 0.06 from the Sloan Digital Sky Survey Data Release 4
using the m = 1 azimuthal Fourier mode. We show that the lopsided distribution
of light is primarily due to a corresponding lopsidedness in the stellar mass
distribution. Observational effects, such as seeing, Poisson noise, and
inclination, introduce only small errors in lopsidedness for the majority of
this sample. We find that lopsidedness correlates strongly with other basic
galaxy structural parameters: galaxies with low concentration, stellar mass,
and stellar surface mass density tend to be lopsided, while galaxies with high
concentration, mass, and density are not. We find that the strongest and most
fundamental relationship between lopsidedness and the other structural
parameters is with the surface mass density. We also find, in agreement with
previous studies, that lopsidedness tends to increase with radius. Both these
results may be understood as a consequence of several factors. The outer
regions of galaxies and low-density galaxies are more susceptible to tidal
perturbations, and they also have longer dynamical times (so lopsidedness will
last longer). They are also more likely to be affected by any underlying
asymmetries in the dark matter halo.Comment: 42 pages, 13 figures, 3 tables, accepted to Ap
The Lopsidedness of Present-Day Galaxies: Connections to the Formation of Stars, the Chemical Evolution of Galaxies, and the Growth of Black Holes
We have used the Sloan Digital Sky Survey (SDSS) to undertake an
investigation of lopsidedness in a sample of ~25,000 nearby galaxies (z <
0.06). We use the m=1 azimuthal Fourier mode between the 50% and 90% light
radii as our measure of lopsidedness. The SDSS spectra are used to measure the
properties of the stars, gas, and black hole in the central-most few-kpc-scale
region. We show that there is a strong link between lopsidedness in the outer
parts of the galactic disk and the youth of the stellar population in the
central region. This link is independent of the other structural properties of
the galaxy. These results provide a robust statistical characterization of the
connections between accretion/interactions/mergers and the resulting star
formation. We also show that residuals in the galaxy mass-metallicity relation
correlate with lopsidedness (at fixed mass, the more metal-poor galaxies are
more lopsided). This suggests that the events causing lopsidedness and enhanced
star formation deliver lower metallicity gas into the galaxy's central region.
Finally, we find that there is a trend for the more powerful active galactic
nuclei to be hosted by more lopsided galaxies (at fixed galaxy mass, density,
or concentration). However if we compare samples matched to have both the same
structures and central stellar populations, we then find no difference in
lopsidedness between active and non-active galaxies. This leads to the
following picture. The presence of cold gas in the central region of a galaxy
(irrespective of its origin) is essential for both star-formation and black
hole growth. The delivery of cold gas is aided by the processes that produce
lopsidedness. Other processes on scales smaller than we can probe with our data
are required to transport the gas to the black hole.Comment: 39 pages, 16 figures, 3 tables, accepted to ApJ. Updated author
affiliation
The sources of sex differences in aging in annual fishes
Intersexual differences in life span (age at death) and aging (increase in mortality risk associated with functional deterioration) are widespread among animals, from nematodes to humans. Males often live shorter than females, but there is substantial unexplained variation among species and populations. Despite extensive research, it is poorly understood how life span differences between the sexes are modulated by an interplay among genetic, environmental and social factors. The goal of our study was to test how sex differences in life span and ageing are modulated by social and environmental factors, and by intrinsic differences between males and females. To disentangle the complex basis of sex differences in life span and aging, we combined comparative data from sex ratios in 367 natural populations of four species of African annual killifish with experimental results on sex differences in life span and aging from eight laboratory populations tested in treatments that varied social and environmental conditions. In the wild, females consistently outlived males. In captivity, sex-specific mortality depended on social conditions. In social-housed experimental groups, male-biased mortality persisted in two aggressive species, but ceased in two placid species. When social and physical contacts were prevented by housing all fish individually, male-biased mortality ceased in all four species. This outcome held across benign and challenging environmental conditions. Fitting demographic survival models revealed that increased baseline mortality was primarily responsible for a shorter male life span in social-housing conditions. The timing and rate of aging were not different between the sexes. No marker of functional aging we recorded in our study (lipofuscin accumulation, proliferative changes in kidney and liver) differed between males and females, despite their previously confirmed association with functional aging in Nothobranchius killifish. We show that sex differences in life span and aging in killifish are driven by a combination of social and environmental conditions, rather than differential functional aging. They are primarily linked to sexual selection but precipitated through multiple processes (predation, social interference). This demonstrates how sex-specific mortality varies among species even within an ecologically and evolutionary discrete lineage and explains how external factors mediate this difference
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