255 research outputs found

    Reassessment of the genus Lophurella (Rhodomelaceae, Rhodophyta) from Australia and New Zealand reveals four cryptic species

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    © 2019, © 2019 British Phycological Society. Cryptic diversity is common in the red algae and is often discovered when comparing specimens from distant locations or different morphotypes of species with high phenotypic plasticity. The genus Lophurella includes seven species from the cold-temperate coasts of the southern hemisphere. L. periclados is the only species reported from Australia where two morphotypes were identified in relation to levels of wave exposure. In New Zealand, three species of Lophurella have been reported–the endemic L. caespitosa (type locality Parimahu, North Island of New Zealand), L. hookeriana (type locality Cape Horn, South America) and L. periclados. We reassessed species diversity of Lophurella in Australia and New Zealand with the aim of determining (1) whether New Zealand and South American specimens of L. hookeriana actually represent a single species, and (2) if the morphotypes of L. periclados mask cryptic diversity. We studied rbcL sequences and morphological features of 36 specimens identified as L. periclados, one specimen of L. caespitosa, and five samples of L. hookeriana, three from New Zealand and two from Cape Horn. Molecular analyses revealed that L. hookeriana from New Zealand and South America are distinct species and the new species L. pauciramulosa is described from New Zealand. L. periclados is a complex involving four species and we propose three new species, L. mutabilis, L. nigra and L. tasmanica. Cryptic diversity in L. periclados did not align with the previously defined ecotypes and several species were often found at the same site. L. periclados, L. nigra and L. tasmanica can be distinguished by morphological characters. Conversely, L. mutabilis has high morphological plasticity, with characters that overlap with L. periclados and L. nigra, and can only be distinguished by DNA sequences

    Grain Surface Models and Data for Astrochemistry

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    AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∌25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions

    The APOE E4 allele is associated with faster rates of neuroretinal thinning in a prospective cohort study of suspect and early glaucoma

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    Purpose: To investigate the association between the apolipoprotein E (APOE) E4 dementia-risk allele and prospective longitudinal retinal thinning in a cohort study of suspect and early manifest glaucoma. Design: Retrospective analysis of prospective cohort data. Participants: This study included all available eyes from participants recruited to the Progression Risk of Glaucoma: Relevant SNPs [single nucleotide polymorphisms] with Significant Association (PROGRESSA) study with genotyping data from which APOE genotypes could be determined. Methods: Apolipoprotein E alleles and genotypes were determined in PROGRESSA, and their distributions were compared with an age-matched and ancestrally matched normative cohort, the Blue Mountains Eye Study. Structural parameters of neuroretinal atrophy measured using spectral-domain OCT were compared within the PROGRESSA cohort on the basis of APOE E4 allele status. Main Outcome Measures: Longitudinal rates of thinning in the macular ganglion celleinner plexiform layer (mGCIPL) complex and the peripapillary retinal nerve fiber layer (pRNFL). Results: Rates of mGCIPL complex thinning were faster in participants harboring ≄1 copies of the APOE E4 allele (b ÂŒ e0.13 mm/year; P ≀0.001). This finding was strongest in eyes affected by normal-tension glaucoma (NTG; b ÂŒ e0.20 mm/year; P ÂŒ 0.003). Apolipoprotein E E4 allele carriers were also more likely to be lost to followup (P ÂŒ 0.01) and to demonstrate a thinner average mGCIPL complex (70.9 mm vs. 71.9 mm; P ÂŒ 0.011) and pRNFL (77.6 mm vs. 79.2 mm; P ÂŒ 0.045) after a minimum of 3 years of monitoring. Conclusions: The APOE E4 allele was associated with faster rates of mCGIPL complex thinning, particularly in eyes with NTG. These results suggest that the APOE E4 allele may be a risk factor for retinal ganglion cell degeneration in glaucoma.Sean Mullany, Henry Marshall, Santiago Diaz-Torres, Ella C. Berry, Joshua M. Schmidt, Daniel Thomson, Ayub Qassim, Minh-Son To, David Dimasi, Abraham Kuot, Lachlan S.W. Knight, Georgina Hollitt, Antonia Kolovos, Angela Schulz, Stewart Lake, Richard A. Mills, Ashish Agar, Anna Galanopoulos, John Landers, Paul Mitchell, Paul R. Healey, Stuart L. Graham, Alex W. Hewitt, Emmanuelle Souzeau, Mark M. Hassall, Sonja Klebe, Stuart MacGregor, Puya Gharahkhani, Robert J. Casson, Owen M. Siggs, Jamie E. Crai

    Reduction in Subtypes and Sizes of Myocardial Infarction With Ticagrelor in PEGASUS-TIMI 54

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    Background: Ticagrelor reduced cardiovascular death, myocardial infarction (MI), or stroke in patients with prior MI in PEGASUSTIMI 54 (Prevention of Cardiovascular Events [eg, Death From Heart or Vascular Disease, Heart Attack, or Stroke] in Patients With Prior Heart Attack Using Ticagrelor Compared to Placebo on a Background of Aspirin). MI can occur in diverse settings and with varying severity; therefore, understanding the types and sizes of MI events prevented is of clinical importance. Methods and Results: MIs were adjudicated by a blinded clinical events committee and categorized by subtype and fold elevation of peak cardiac troponin over the upper limit of normal. A total of 1042 MIs occurred in 898 of the 21 162 randomized patients over a median follow-up of 33 months. The majority of the MIs (76%) were spontaneous (Type 1), with demand MI (Type 2) and stent thrombosis (Type 4b) accounting for 13% and 9%, respectively; sudden death (Type 3), percutaneous coronary intervention–related (Type 4a) and coronary artery bypass graft–related (Type 5) each accounted for <1%. Half of MIs (520, 50%) had a peak troponin ≄10x upper limit of normal and 21% of MIs (220) had a peak troponin ≄1009 upper limit of normal. A total of 21% (224) were ST-segment–elevation MI STEMI. Overall ticagrelor reduced MI (4.47% versus 5.25%, hazard ratio 0.83, 95% confidence interval 0.72–0.95, P=0.0055). The benefit was consistent among the subtypes, including a 31% reduction in MIs with a peak troponin ≄1009 upper limit of normal (hazard ratio 0.69, 95% confidence interval 0.53–0.92, P=0.0096) and a 40% reduction in ST-segment elevation MI (hazard ratio 0.60, 95% confidence interval 0.46–0.78, P=0.0002). Conclusions: In stable outpatients with prior MI, the majority of recurrent MIs are spontaneous and associated with a high biomarker elevation. Ticagrelor reduces the MI consistently among subtypes and sizes including large MIs and ST-segment elevation MI

    Milagro limits and HAWC sensitivity for the rate-density of evaporating Primordial Black Holes

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    On the sensitivity of the HAWC observatory to gamma-ray bursts

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    We present the sensitivity of HAWC to Gamma Ray Bursts (GRBs). HAWC is a very high-energy gamma-ray observatory currently under construction in Mexico at an altitude of 4100 m. It will observe atmospheric air showers via the water Cherenkov method. HAWC will consist of 300 large water tanks instrumented with 4 photomultipliers each. HAWC has two data acquisition (DAQ) systems. The main DAQ system reads out coincident signals in the tanks and reconstructs the direction and energy of individual atmospheric showers. The scaler DAQ counts the hits in each photomultiplier tube (PMT) in the detector and searches for a statistical excess over the noise of all PMTs. We show that HAWC has a realistic opportunity to observe the high-energy power law components of GRBs that extend at least up to 30 GeV, as it has been observed by Fermi LAT. The two DAQ systems have an energy threshold that is low enough to observe events similar to GRB 090510 and GRB 090902b with the characteristics observed by Fermi LAT. HAWC will provide information about the high-energy spectra of GRBs which in turn could help to understanding about e-pair attenuation in GRB jets, extragalactic background light absorption, as well as establishing the highest energy to which GRBs accelerate particles
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