28 research outputs found
Precursor flares in OJ 287
We have studied three most recent precursor flares in the light curve of the
blazar OJ 287 while invoking the presence of a precessing binary black hole in
the system to explain the nature of these flares. Precursor flare timings from
the historical light curves are compared with theoretical predictions from our
model that incorporate effects of an accretion disk and post-Newtonian
description for the binary black hole orbit. We find that the precursor flares
coincide with the secondary black hole descending towards the accretion disk of
the primary black hole from the observed side, with a mean z-component of
approximately z_c = 4000 AU. We use this model of precursor flares to predict
that precursor flare of similar nature should happen around 2020.96 before the
next major outburst in 2022.Comment: to appear in the Astrophysical Journa
Recommended from our members
Genomics of the hop pseudo-autosomal regions
Hop is one of the few dioecious plants with dimorphic sex chromosomes. Because the entire Cannabaceae family is dioecious, hop and other members of this family are thought to have a relatively older sex chromosomal system than other plant species. Hop cones are only produced in female hops with or without fertilization. This has lead to most genomic research being directed toward female plants. The work we present provides genomic resources surrounding male plants. We have produced a draft genome for the male hop line USDA 21422M using a novel genome assembly method. In addition, we identified a 1.3 Mb set of scaffolds, which appear to be the male specific region based upon specificity with male hop accessions. This set includes a smaller high confidence total length 18 Kb set of scaffolds, which are supported by over 500 individuals, including the USDA world collection of hop varieties and two mapping populations, with genotyping by sequencing. We also have identified a portion of the Teamaker × 21422M linkage map to be associated with the pseudo-autosomal region (PAR). Within the genomic scaffolds, we identified a set of genes that are sex-linked and likely located in the PAR.Keywords: Pseudoautosomal region, Genomics, Sexual determining region, Humulus, Sex chromosome
Recommended from our members
HillGenomicsHopPseudoAutosomalRegions.pdf
Hop is one of the few dioecious plants with dimorphic sex chromosomes. Because the entire Cannabaceae family is dioecious, hop and other members of this family are thought to have a relatively older sex chromosomal system than other plant species. Hop cones are only produced in female hops with or without fertilization. This has lead to most genomic research being directed toward female plants. The work we present provides genomic resources surrounding male plants. We have produced a draft genome for the male hop line USDA 21422M using a novel genome assembly method. In addition, we identified a 1.3 Mb set of scaffolds, which appear to be the male specific region based upon specificity with male hop accessions. This set includes a smaller high confidence total length 18 Kb set of scaffolds, which are supported by over 500 individuals, including the USDA world collection of hop varieties and two mapping populations, with genotyping by sequencing. We also have identified a portion of the Teamaker × 21422M linkage map to be associated with the pseudo-autosomal region (PAR). Within the genomic scaffolds, we identified a set of genes that are sex-linked and likely located in the PAR.Keywords: Pseudoautosomal region, Humulus, Sexual determining region, Sex chromosomes, Genomic
Recommended from our members
HillGenomicsHopPseudoAutosomalRegionsSup3.xlsx
Hop is one of the few dioecious plants with dimorphic sex chromosomes. Because the entire Cannabaceae family is dioecious, hop and other members of this family are thought to have a relatively older sex chromosomal system than other plant species. Hop cones are only produced in female hops with or without fertilization. This has lead to most genomic research being directed toward female plants. The work we present provides genomic resources surrounding male plants. We have produced a draft genome for the male hop line USDA 21422M using a novel genome assembly method. In addition, we identified a 1.3 Mb set of scaffolds, which appear to be the male specific region based upon specificity with male hop accessions. This set includes a smaller high confidence total length 18 Kb set of scaffolds, which are supported by over 500 individuals, including the USDA world collection of hop varieties and two mapping populations, with genotyping by sequencing. We also have identified a portion of the Teamaker × 21422M linkage map to be associated with the pseudo-autosomal region (PAR). Within the genomic scaffolds, we identified a set of genes that are sex-linked and likely located in the PAR.Keywords: Sexual determining region, Genomics, Sex chromosomes, Pseudoautosomal region, HumulusKeywords: Sexual determining region, Genomics, Sex chromosomes, Pseudoautosomal region, Humulu
Precursor flares in OJ 287
We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain the nature of these flares. Precursor flare timings from the historical light curves are compared with theoretical predictions from our model that incorporate effects of an accretion disk and post-Newtonian description for the binary black hole orbit. We find that the precursor flares coincide with the secondary black hole descending toward the accretion disk of the primary black hole from the observed side, with a mean z-component of approximately zc = 4000 AU. We use this model of precursor flares to predict that precursor flare of similar nature should happen around 2020.96 before the next major outburst in 2022. © 2013. The American Astronomical Society. All rights reserved.
Tadalafil increases muscle capillary recruitment and forearm glucose uptake in women with type 2 diabetes
Recommended from our members
Pneumonia in Bighorn Sheep: Risk and Resilience
Infectious disease contributed to historical declines and extirpations of bighorn sheep (Ovis canadensis) in North America and continues to impede population restoration and management. Reports of pneumonia outbreaks in free‐ranging bighorn sheep following contact with domestic sheep have been validated by the results of 13 captive commingling experiments. However, ecological and etiological complexities still hinder our understanding and control of respiratory disease in wild sheep. In this paper, we review the literature and summarize recent data to present an overview of the biology and management of pneumonia in bighorn sheep. Many factors contribute to this population‐limiting disease, but a bacterium (Mycoplasma ovipneumoniae) host‐specific to Caprinae and commonly carried by healthy domestic sheep and goats, appears to be a primary agent necessary for initiating epizootics. All‐age epizootics are usually associated with significant population declines, but mortality rates vary widely and factors influencing disease severity are not well understood. Once introduced, M. ovipneumoniae can persist in bighorn sheep populations for decades. Carrier females may transmit the pathogen to their susceptible lambs, triggering fatal pneumonia outbreaks in nursery groups, which limit recruitment and slow or prevent population recovery. The demographic costs of disease persistence can be equal to or greater than the impacts of the initial epizootic. Strain typing suggests that spillover of M. ovipneumoniae into bighorn sheep populations from domestic small ruminants is ongoing and that consequences of spillover are amplified by movements of infected bighorn sheep across populations. Therefore, current disease management strategies focus on reducing risk of spillover from reservoir populations of domestic sheep and goats and on limiting transmission among bighorn sheep. A variety of techniques are employed to prevent contacts that could lead to transmission, including limiting the numbers and distribution of both wild and domestic species. No vaccine or antibiotic treatment has controlled infection in domestic or wild sheep and to date, management actions have been unsuccessful at reducing morbidity, mortality, or disease spread once a bighorn sheep population has been exposed. More effective strategies are needed to prevent pathogen introduction, induce disease fadeout in persistently infected populations, and promote population resilience across the diverse landscapes bighorn sheep inhabit. A comprehensive examination of disease dynamics across populations could help elucidate how disease sometimes fades out naturally and whether population resilience can be increased in the face of infection. Cross‐jurisdictional adaptive management experiments and transdisciplinary collaboration, including partnerships with members of the domestic sheep and goat community, are needed to speed progress toward sustainable solutions to protect and restore bighorn sheep populations. © 2017 The Wildlife Society