8 research outputs found
Radio Emission and AGN Feedback in Post-starburst Galaxies
We investigate radio-mode AGN activity among post-starburst galaxies from the
Sloan Digital Sky Survey to determine whether AGN feedback may be responsible
for the cessation of star formation. Based on radio morphology and
radio-loudness from the FIRST and NVSS data, we separate objects with radio
activity due to an AGN from ongoing residual star formation. Of 513 SDSS
galaxies with strong A-star spectra, 12 objects have 21-cm flux density above 1
mJy. These galaxies do not show optical AGN emission lines. Considering that
the lifetime of radio emission is much shorter than the typical time-scale of
the spectroscopic features of post-starburst galaxies, we conclude that the
radio-emitting AGN activity in these objects was triggered after the end of the
recent starburst, and thus cannot be an important feedback process to explain
the post-starburst phase. The radio luminosities show a positive correlation
with total galaxy stellar mass, but not with the mass of recently formed stars.
Thus the mechanical power of AGN feedback derived from the radio luminosity is
related to old stellar populations dominating the stellar mass, which in turn
are related to the masses of central supermassive black holes.Comment: 11 pages, 6 figures, accepted for publication in MNRA
Genotype, haplotype and copy-number variation in worldwide human populations
Genome-wide patterns of variation across individuals provide a powerful source of data for uncovering the history of migration, range expansion, and adaptation of the human species. However, high-resolution surveys of variation in genotype, haplotype and copy number have generally focused on a small number of population groups(1-3). Here we report the analysis of high-quality genotypes at 525,910 single-nucleotide polymorphisms ( SNPs) and 396 copy-number-variable loci in a worldwide sample of 29 populations. Analysis of SNP genotypes yields strongly supported fine-scale inferences about population structure. Increasing linkage disequilibrium is observed with increasing geographic distance from Africa, as expected under a serial founder effect for the out-of-Africa spread of human populations. New approaches for haplotype analysis produce inferences about population structure that complement results based on unphased SNPs. Despite a difference from SNPs in the frequency spectrum of the copy-number variants (CNVs) detected-including a comparatively large number of CNVs in previously unexamined populations from Oceania and the Americas-the global distribution of CNVs largely accords with population structure analyses for SNP data sets of similar size. Our results produce new inferences about inter-population variation, support the utility of CNVs in human population-genetic research, and serve as a genomic resource for human-genetic studies in diverse worldwide populations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62552/1/nature06742.pd
Lens stem cells may reside outside the lens capsule: an hypothesis
In this paper, we consider the ocular lens in the context of contemporary developments in biological ideas. We attempt to reconcile lens biology with stem cell concepts and a dearth of lens tumors
‘The lived experience of nurses during covid-19’: A collaborative project between QUB, KCL, and RCN NI
To record the lived experiences of nurses during Covid-19 the Royal College of Nursing Northern Ireland (RCN NI) designed a survey, using SenseMaker, which has provided evidence of a unique social history of nursing during a 21st century global pandemic. Staff at RCN NI, Queens University, Belfast (QUB) and King's College London (KCL) collaborated in the development and recording of a film where nursing students and staff performed verbatim dialogue from interviews with nurses during COVID-19 recorded in the SenseMaker survey. Aligning with this, QUB are conducting a research study via a qualitative survey and audience participation to explore the impact of this work. The project was launched at the headquarters of the RCN NI on 8th February 2024