98 research outputs found
The population of planetary nebulae and HII regions in M81. A study of radial metallicity gradients and chemical evolution
We analyze the chemical abundances of planetary nebulae and HII regions in
the M81 disk for insight on galactic evolution, and compare it with that of
other galaxies, including the Milky Way. We acquired Hectospec/MMT spectra of
39 PNe and 20 HII regions, with 33 spectra viable for temperature and abundance
analysis. Our PN observations represent the first PN spectra in M81 ever
published, while several HII region spectra have been published before,
although without a direct electron temperature determination. We determine
elemental abundances of helium, nitrogen, oxygen, neon, sulfur, and argon in
PNe and HII regions, and determine their averages and radial gradients. The
average O/H ratio of PNe compared to that of the HII regions indicates a
general oxygen enrichment in M81 in the last ~10 Gyr. The PN metallicity
gradient in the disk of M81 is -0.055+-0.02 dex/kpc. Neon and sulfur in PNe
have a radial distribution similar to that of oxygen, with similar gradient
slopes. If we combine our HII sample with the one in the literature we find a
possible mild evolution of the gradient slope, with results consistent with
gradient steepening with time. Additional spectroscopy is needed to confirm
this trend. There are no Type I PNe in our M81 sample, consistently with the
observation of only the brightest bins of the PNLF, the galaxy metallicity, and
the evolution of post-AGB shells. Both the young and the old populations of M81
disclose shallow but detectable negative radial metallicity gradient, which
could be slightly steeper for the young population, thus not excluding a mild
gradients steepening with the time since galaxy formation. During its evolution
M81 has been producing oxygen; its total oxygen enrichment exceeds that of
other nearby galaxies.Comment: A&A, in pres
Animation by Computer. a Tool for Understanding the Dynamical Behaviour of Ancient Machines
The datasets in this article are associated with the research article \u27Assessing biological and environmental effects of a total solar eclipse with passive multimodal technologies\u27 (Brinley Buckley et al., 2018). We documented biotic and abiotic changed during a total solar eclipse on 21 August 2017, in south-central Nebraska, USA, with a multimodel suite of tools, including time-lapse camera systems, data loggers, and sound recording devices. Time-lapse images were used to approximate changes in light, data loggers were used to record temperature and humidity, and sound recordings were used to calculate acoustic indices characterizing variation in the soundscape, as well as to manually identify and estimate avian vocalization activity
Associations of NINJ2 sequence variants with incident ischemic stroke in the Cohorts for Heart and Aging in Genomic Epidemiology (CHARGE) consortium
Background<p></p>
Stroke, the leading neurologic cause of death and disability, has a substantial genetic component. We previously conducted a genome-wide association study (GWAS) in four prospective studies from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium and demonstrated that sequence variants near the NINJ2 gene are associated with incident ischemic stroke. Here, we sought to fine-map functional variants in the region and evaluate the contribution of rare variants to ischemic stroke risk.<p></p>
Methods and Results<p></p>
We sequenced 196 kb around NINJ2 on chromosome 12p13 among 3,986 European ancestry participants, including 475 ischemic stroke cases, from the Atherosclerosis Risk in Communities Study, Cardiovascular Health Study, and Framingham Heart Study. Meta-analyses of single-variant tests for 425 common variants (minor allele frequency [MAF] ℠1%) confirmed the original GWAS results and identified an independent intronic variant, rs34166160 (MAF = 0.012), most significantly associated with incident ischemic stroke (HR = 1.80, p = 0.0003). Aggregating 278 putatively-functional variants with MAF†1% using count statistics, we observed a nominally statistically significant association, with the burden of rare NINJ2 variants contributing to decreased ischemic stroke incidence (HR = 0.81; p = 0.026).<p></p>
Conclusion<p></p>
Common and rare variants in the NINJ2 region were nominally associated with incident ischemic stroke among a subset of CHARGE participants. Allelic heterogeneity at this locus, caused by multiple rare, low frequency, and common variants with disparate effects on risk, may explain the difficulties in replicating the original GWAS results. Additional studies that take into account the complex allelic architecture at this locus are needed to confirm these findings
It\u27s Time to Listen: There is Much to be Learned from the Sounds of Tropical Ecosystems
Knowledge that can be gained from acoustic data collection in tropical ecosystems is lowâhanging fruit. There is every reason to record and with every day, there are fewer excuses not to do it. In recent years, the cost of acoustic recorders has decreased substantially (some can be purchased for under US$50, e.g., Hill et al. 2018) and the technology needed to store and analyze acoustic data is continuously improving (e.g., Corrada Bravo et al. 2017, Xie et al. 2017). Soundscape recordings provide a permanent record of a site at a given time and contain a wealth of invaluable and irreplaceable information. Although challenges remain, failure to collect acoustic data now in tropical ecosystems would represent a failure to future generations of tropical researchers and the citizens that benefit from ecological research. In this commentary, we (1) argue for the need to increase acoustic monitoring in tropical systems; (2) describe the types of research questions and conservation issues that can be addressed with passive acoustic monitoring (PAM) using both shortâ and longâterm data in terrestrial and freshwater habitats; and (3) present an initial plan for establishing a global repository of tropical recordings
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Erratum: Sequence data and association statistics from 12,940 type 2 diabetes cases and controls.
This corrects the article DOI: 10.1038/sdata.2017.179
Inhibition of Multidrug Resistance by SV40 Pseudovirion Delivery of an Antigene Peptide Nucleic Acid (PNA) in Cultured Cells
Peptide nucleic acid (PNA) is known to bind with extraordinarily high affinity and sequence-specificity to complementary nucleic acid sequences and can be used to suppress gene expression. However, effective delivery into cells is a major obstacle to the development of PNA for gene therapy applications. Here, we present a novel method for the in vitro delivery of antigene PNA to cells. By using a nucleocapsid protein derived from Simian virus 40, we have been able to package PNA into pseudovirions, facilitating the delivery of the packaged PNA into cells. We demonstrate that this system can be used effectively to suppress gene expression associated with multidrug resistance in cancer cells, as shown by RT-PCR, flow cytometry, Western blotting, and cell viability under chemotherapy. The combination of PNA with the SV40-based delivery system is a method for suppressing a gene of interest that could be broadly applied to numerous targets
Genetic identification of a common collagen disease in Puerto Ricans via identity-by-descent mapping in a health system
Achieving confidence in the causality of a disease locus is a complex task that often requires supporting data from both statistical genetics and clinical genomics. Here we describe a combined approach to identify and characterize a genetic disorder that leverages distantly related patients in a health system and population-scale mapping. We utilize genomic data to uncover components of distant pedigrees, in the absence of recorded pedigree information, in the multi-ethnic BioMe biobank in New York City. By linking to medical records, we discover a locus associated with both elevated genetic relatedness and extreme short stature. We link the gene, COL27A1, with a little-known genetic disease, previously thought to be rare and recessive. We demonstrate that disease manifests in both heterozygotes and homozygotes, indicating a common collagen disorder impacting up to 2% of individuals of Puerto Rican ancestry, leading to a better understanding of the continuum of complex and Mendelian disease
Validation of the Body Concealment Scale for Scleroderma (BCSS): Replication in the Scleroderma Patient-centered Intervention Network (SPIN) Cohort
© 2016 Elsevier Ltd Body concealment is an important component of appearance distress for individuals with disfiguring conditions, including scleroderma. The objective was to replicate the validation study of the Body Concealment Scale for Scleroderma (BCSS) among 897 scleroderma patients. The factor structure of the BCSS was evaluated using confirmatory factor analysis and the Multiple-Indicator Multiple-Cause model examined differential item functioning of SWAP items for sex and age. Internal consistency reliability was assessed via Cronbach's alpha. Construct validity was assessed by comparing the BCSS with a measure of body image distress and measures of mental health and pain intensity. Results replicated the original validation study, where a bifactor model provided the best fit. The BCSS demonstrated strong internal consistency reliability and construct validity. Findings further support the BCSS as a valid measure of body concealment in scleroderma and provide new evidence that scores can be compared and combined across sexes and ages
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