581 research outputs found
Three Different Types of Galaxy Alignment within Dark Matter Halos
Using a large galaxy group catalogue based on the Sloan Digital Sky Survey
Data Release 4 we measure three different types of intrinsic galaxy alignment
within groups: halo alignment between the orientation of the brightest group
galaxies (BGG) and the distribution of its satellite galaxies, radial alignment
between the orientation of a satellite galaxy and the direction towards its
BGG, and direct alignment between the orientation of the BGG and that of its
satellites. In agreement with previous studies we find that satellite galaxies
are preferentially located along the major axis. In addition, on scales r < 0.7
Rvir we find that red satellites are preferentially aligned radially with the
direction to the BGG. The orientations of blue satellites, however, are
perfectly consistent with being isotropic. Finally, on scales r < 0.1 \Rvir, we
find a weak but significant indication for direct alignment between satellites
and BGGs. We briefly discuss the implications for weak lensing measurements.Comment: 4 pages, 4 figures, ApJL accepte
Spatial and kinematic alignments between central and satellite halos
Based on a cosmological N-body simulation we analyze spatial and kinematic
alignments of satellite halos within six times the virial radius of group size
host halos (Rvir). We measure three different types of spatial alignment: halo
alignment between the orientation of the group central substructure (GCS) and
the distribution of its satellites, radial alignment between the orientation of
a satellite and the direction towards its GCS, and direct alignment between the
orientation of the GCS and that of its satellites. In analogy we use the
directions of satellite velocities and probe three further types of alignment:
the radial velocity alignment between the satellite velocity and connecting
line between satellite and GCS, the halo velocity alignment between the
orientation of the GCS and satellite velocities and the auto velocity alignment
between the satellites orientations and their velocities. We find that
satellites are preferentially located along the major axis of the GCS within at
least 6 Rvir (the range probed here). Furthermore, satellites preferentially
point towards the GCS. The most pronounced signal is detected on small scales
but a detectable signal extends out to 6 Rvir. The direct alignment signal is
weaker, however a systematic trend is visible at distances < 2 Rvir. All
velocity alignments are highly significant on small scales. Our results suggest
that the halo alignment reflects the filamentary large scale structure which
extends far beyond the virial radii of the groups. In contrast, the main
contribution to the radial alignment arises from the adjustment of the
satellite orientations in the group tidal field. The projected data reveal good
agreement with recent results derived from large galaxy surveys. (abridged)Comment: accepted for publication in Ap
Prostate-specific antigen patterns in US and European populations:Comparison of six diverse cohorts
Objective: To determine whether there are differences in prostate-specific antigen (PSA) levels at diagnosis or changes in PSA levels between US and European populations of men with and without prostate cancer (PCa). Subjects and Methods: We analysed repeated measures of PSA from six clinically and geographically diverse cohorts of men: two cohorts with PSA-detected PCa, two cohorts with clinically detected PCa and two cohorts without PCa. Using multilevel models, average PSA at diagnosis and PSA change over time were compared among study populations. Results: The annual percentage PSA change of 4-5% was similar between men without cancer and men with PSA-detected cancer. PSA at diagnosis was 1.7 ng/mL lower in a US cohort of men with PSA-detected PCa (95% confidence interval 1.3-2.0 ng/mL), compared with a UK cohort of men with PSA-detected PCa, but there was no evidence of a different rate of PSA change between these populations. Conclusion: We found that PSA changes over time are similar in UK and US men diagnosed through PSA testing and even in men without PCa. Further development of PSA models to monitor men on active surveillance should be undertaken in order to take advantage of these similarities. We found no evidence that guidelines for using PSA to monitor men cannot be passed between US and European studies
Haptoglobin Genotype Does Not Confer a Risk of Stroke in Type 1 Diabetes
The exon copy number variant in the haptoglobin gene is associated with cardiovascular and kidney disease. For stroke, previous research is inconclusive. We aimed to study the relationship between haptoglobin Hp1/2 genotype and stroke in individuals with type 1 diabetes from the Finnish Diabetic Nephropathy Study. We included two partially overlapping cohorts: one with haptoglobin genotypes determined using genotyping for 179 stroke cases and 517 matched controls, and the other using haptoglobin genotype imputation for a larger cohort of 500 stroke cases and 3,806 controls. We observed no difference in the Hp1-1, Hp2-1, and Hp2-2 genotype frequencies between the stroke cases and controls, neither in the genotyping nor the imputation cohorts. Haptoglobin genotypes were also not associated with the ischemic or hemorrhagic stroke subtypes. In our imputed haptoglobin cohort, 61% of individuals with stroke died during follow-up. However, the risk of death was not related to the haptoglobin genotype. Diabetic kidney disease and cardiovascular events were common in the cohort, but the haptoglobin genotypes were not associated with stroke when stratified by these complications. To conclude, the Hp1/2 genotypes did not affect the risk of stroke or survival after stroke in our type 1 diabetes cohort.Peer reviewe
Sociodemographic variation in the use of chemotherapy and radiotherapy in patients with stage IV lung, oesophageal, stomach and pancreatic cancer: evidence from population-based data in England during 2013-2014.
BACKGROUND: Sociodemographic inequalities in cancer treatment have been generally described, but there is little evidence regarding patients with advanced cancer. Understanding variation in the management of these patients may provide insights into likely mechanisms leading to inequalities in survival. METHODS: We identified 50,232 patients with stage IV lung, oesophageal, pancreatic and stomach cancer from the English national cancer registry. A generalised linear model with a Poisson error structure was used to explore variation in radiotherapy and chemotherapy within 6 months from diagnosis by age, sex, deprivation, ethnicity, cancer site, comorbidity and, additionally, performance status. RESULTS: There was substantial variation by cancer site, large gradients by age, and non-trivial associations with comorbidity and deprivation. After full adjustment, more deprived patients were consistently least likely to be treated with chemotherapy alone or chemotherapy and radiotherapy combined compared with less deprived patients with equally advanced disease stage (treatment rate ratio: 0.82 95% CI (0.78, 0.87) for CT, 0.78 95% CI (0.71, 0.85) for CTRT pā<ā0.0001). CONCLUSIONS: There was marked variation in the management of patients with stage IV cancer. Routinely collected data could be used for surveillance across all cancers to help reduce treatment variation and optimise outcomes among patients with advanced cancer
Unagreement is an illusion
This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s11049-015-9311-yThis paper proposes an analysis of unagreement, a phenomenon involving an apparent mismatch between a definite third person plural subject and first or second person plural subject agreement observed in various null subject languages (e.g. Spanish, Modern Greek and Bulgarian), but notoriously absent in others (e.g. Italian, European Portuguese). A cross-linguistic correlation between unagreement and the structure of adnominal pronoun constructions suggests that the availability of unagreement depends on whether person and definiteness are hosted by separate heads (in languages like Greek) or bundled on a single head (i.e. pronominal determiners in languages like Italian). Null spell-out of the head hosting person features high in the extended nominal projection of the subject leads to unagreement. The lack of unagreement in languages with pronominal determiners results from the interaction of their syntactic structure with the properties of the vocabulary items realising the head encoding both person and definiteness. The analysis provides a principled explanation for the cross-linguistic distribution of unagreement and suggests a unified framework for deriving unagreement, adnominal pronoun constructions, personal pronouns and pro
PDGF and PDGF receptors in glioma
The family of platelet-derived growth factors (PDGFs) plays a number of critical roles in normal embryonic development, cellular differentiation, and response to tissue damage. Not surprisingly, as it is a multi-faceted regulatory system, numerous pathological conditions are associated with aberrant activity of the PDGFs and their receptors. As we and others have shown, human gliomas, especially glioblastoma, express all PDGF ligands and both the two cell surface receptors, PDGFR-Ī± and -Ī². The cellular distribution of these proteins in tumors indicates that glial tumor cells are stimulated via PDGF/PDGFR-Ī± autocrine and paracrine loops, while tumor vessels are stimulated via the PDGFR-Ī². Here we summarize the initial discoveries on the role of PDGF and PDGF receptors in gliomas and provide a brief overview of what is known in this field
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