The Vortex-Wave equation with a single vortex as the limit of the Euler equation

In this article we consider the physical justification of the Vortex-Wave equation introduced by Marchioro and Pulvirenti in the case of a single point vortex moving in an ambient vorticity. We consider a sequence of solutions for the Euler equation in the plane corresponding to initial data consisting of an ambient vorticity in $L^1\cap L^\infty$ and a sequence of concentrated blobs which approach the Dirac distribution. We introduce a notion of a weak solution of the Vortex-Wave equation in terms of velocity (or primitive variables) and then show, for a subsequence of the blobs, the solutions of the Euler equation converge in velocity to a weak solution of the Vortex-Wave equation.Comment: 24 pages, to appea

Non-linear screening corrections of stellar nuclear reaction rates and their effects on solar neutrino fluxes

Non-linear electron screening corrections of stellar nuclear fusion rates are calculated analytically in the framework of the Debye-Huckel model and compared with the respective ones of Salpeter's weak screening approximation. In typical solar conditions, the deviation from Salpeter's screening factor is less than one percent, while for hotter stars such corrections turn out to be of the order of one percent only over the limits of the Debye-Huckel model. Moreover, an investigation of the impact of the derived non-linear screening effects on the solar neutrino fluxes yields insignificant corrections for both the pp and CNO chain reactions.Comment: To appear in Phys.Rev.

Analytically Solvable Asymptotic Model of Atrial Excitability

We report a three-variable simplified model of excitation fronts in human atrial tissue. The model is derived by novel asymptotic techniques \new{from the biophysically realistic model of Courtemanche et al (1998) in extension of our previous similar models. An iterative analytical solution of the model is presented which is in excellent quantitative agreement with the realistic model. It opens new possibilities for analytical studies as well as for efficient numerical simulation of this and other cardiac models of similar structure

Reducing nitrous oxide emissions by changing N fertiliser use from calcium ammonium nitrate (CAN) to urea based formulations

This research was financially supported under the National Development Plan, through the Research Stimulus Fund, administered by the Department of Agriculture, Food and the Marine (Grant numbers RSF10-/RD/SC/716 and RSF11S138) and from the Department of Agriculture and Rural Development (Ref: DARD Evidence and Innovation project 13/04/06) for Northern Ireland. The first author gratefully acknowledges funding received from the Teagasc Walsh Fellowship Scheme (Ref: 2012005).peer-reviewedThe accelerating use of synthetic nitrogen (N) fertilisers, to meet the world's growing food demand, is the primary driver for increased atmospheric concentrations of nitrous oxide (N2O). The IPCC default emission factor (EF) for N2O from soils is 1% of the N applied, irrespective of its form. However, N2O emissions tend to be higher from nitrate-containing fertilisers e.g. calcium ammonium nitrate (CAN) compared to urea, particularly in regions, which have mild, wet climates and high organic matter soils. Urea can be an inefficient N source due to NH3 volatilisation, but nitrogen stabilisers (urease and nitrification inhibitors) can improve its efficacy. This study evaluated the impact of switching fertiliser formulation from calcium ammonium nitrate (CAN) to urea-based products, as a potential mitigation strategy to reduce N2O emissions at six temperate grassland sites on the island of Ireland. The surface applied formulations included CAN, urea and urea with the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) and/or the nitrification inhibitor dicyandiamide (DCD). Results showed that N2O emissions were significantly affected by fertiliser formulation, soil type and climatic conditions. The direct N2O emission factor (EF) from CAN averaged 1.49% overall sites, but was highly variable, ranging from 0.58% to 3.81. Amending urea with NBPT, to reduce ammonia volatilisation, resulted in an average EF of 0.40% (ranging from 0.21 to 0.69%)-compared to an average EF of 0.25% for urea (ranging from 0.1 to 0.49%), with both fertilisers significantly lower and less variable than CAN. Cumulative N2O emissions from urea amended with both NBPT and DCD were not significantly different from background levels. Switching from CAN to stabilised urea formulations was found to be an effective strategy to reduce N2O emissions, particularly in wet, temperate grassland.Department of Agriculture and Rural Development for Northern IrelandTeagasc Walsh Fellowship ProgrammeDepartment of Agriculture, Food and the Marin

Transcript- and annotation-guided genome assembly of the European starling

First published: 28 June 2022The European starling, Sturnus vulgaris, is an ecologically significant, globally invasive avian species that is also suffering from a major decline in its native range. Here, we present the genome assembly and long- read transcriptome of an Australian-sourced European starling (S. vulgaris vAU), and a second, North American, short- read genome assembly (S. vulgaris vNA), as complementary reference genomes for population genetic and evolutionary characterization. S. vulgaris vAU combined 10× genomics linked- reads, low-coverage Nanopore sequencing, and PacBio Iso-Seq full- length transcript scaffolding to generate a 1050 Mb assembly on 6222 scaffolds (7.6 Mb scaffold N50, 94.6% busco completeness). Further scaffolding against the high-quality zebra finch (Taeniopygia guttata) genome assigned 98.6% of the assembly to 32 puta-tive nuclear chromosome scaffolds. Species-specific transcript mapping and gene an-notation revealed good gene- level assembly and high functional completeness. Using S. vulgaris vAU, we demonstrate how the multifunctional use of PacBio Iso-Seq tran-script data and complementary homology-based annotation of sequential assembly steps (assessed using a new tool, saaga) can be used to assess, inform, and validate assembly workflow decisions. We also highlight some counterintuitive behaviour in traditional busco metrics, and present buscomp, a complementary tool for assembly comparison designed to be robust to differences in assembly size and base-calling quality. This work expands our knowledge of avian genomes and the available toolkit for assessing and improving genome quality. The new genomic resources presented will facilitate further global genomic and transcriptomic analysis on this ecologically important species.Katarina C. Stuart, Richard J. Edwards, Yuanyuan Cheng, Wesley C. Warren, David W. Burt, William B. Sherwin, Natalie R. Hofmeister, Scott J. Werner, Gregory F. Ball, Melissa Bateson, Matthew C. Brandley, Katherine L. Buchanan, Phillip Cassey, David F. Clayton, Tim De Meyer, Simone L. Meddle, Lee A. Rollin

Model confidence sets and forecast combination: an application to age-specific mortality

Background: Model averaging combines forecasts obtained from a range of models, and it often produces more accurate forecasts than a forecast from a single model. Objective: The crucial part of forecast accuracy improvement in using the model averaging lies in the determination of optimal weights from a finite sample. If the weights are selected sub-optimally, this can affect the accuracy of the model-averaged forecasts. Instead of choosing the optimal weights, we consider trimming a set of models before equally averaging forecasts from the selected superior models. Motivated by Hansen et al. (2011), we apply and evaluate the model confidence set procedure when combining mortality forecasts. Data & Methods: The proposed model averaging procedure is motivated by Samuels and Sekkel (2017) based on the concept of model confidence sets as proposed by Hansen et al. (2011) that incorporates the statistical significance of the forecasting performance. As the model confidence level increases, the set of superior models generally decreases. The proposed model averaging procedure is demonstrated via national and sub-national Japanese mortality for retirement ages between 60 and 100+. Results: Illustrated by national and sub-national Japanese mortality for ages between 60 and 100+, the proposed model-average procedure gives the smallest interval forecast errors, especially for males. Conclusion: We find that robust out-of-sample point and interval forecasts may be obtained from the trimming method. By robust, we mean robustness against model misspecification

GH safety workshop position paper: A critical appraisal of recombinant human GH therapy in children and adults

Recombinant human GH (rhGH) has been in use for 30 years, and over that time its safety and efficacy in children and adults has been subject to considerable scrutiny. In 2001, a statement from the GH Research Society (GRS) concluded that 'for approved indications, GH is safe'; however, the statement highlighted a number of areas for on-going surveillance of long-Term safety, including cancer risk, impact on glucose homeostasis, and use of high dose pharmacological rhGH treatment. Over the intervening years, there have been a number of publications addressing the safety of rhGH with regard to mortality, cancer and cardiovascular risk, and the need for long-Term surveillance of the increasing number of adults who were treated with rhGH in childhood. Against this backdrop of interest in safety, the European Society of Paediatric Endocrinology (ESPE), the GRS, and the Pediatric Endocrine Society (PES) convened a meeting to reappraise the safety of rhGH. The ouput of the meeting is a concise position statement

Prospects for Studies of Stellar Evolution and Stellar Death in the JWST Era

I review the prospects for studies of the advanced evolutionary stages of low-, intermediate- and high-mass stars by the JWST and concurrent facilities, with particular emphasis on how they may help elucidate the dominant contributors to the interstellar dust component of galaxies. Observations extending from the mid-infrared to the submillimeter can help quantify the heavy element and dust species inputs to galaxies from AGB stars. JWST's MIRI mid-infrared instrument will be so sensitive that observations of the dust emission from individual intergalactic AGB stars and planetary nebulae in the Virgo Cluster will be feasible. The Herschel Space Observatory will enable the last largely unexplored spectral region, the far-IR to the submillimeter, to be surveyed for new lines and dust features, while SOFIA will cover the wavelength gap between JWST and Herschel, a spectral region containing important fine structure lines, together with key water-ice and crystalline silicate bands. Spitzer has significantly increased the number of Type II supernovae that have been surveyed for early-epoch dust formation but reliable quantification of the dust contributions from massive star supernovae of Type II, Type Ib and Type Ic to low- and high-redshift galaxies should come from JWST MIRI observations, which will be able to probe a volume over 1000 times larger than Spitzer.Comment: 24 pages, 19 figures. To appear in `Astrophysics in the Next Decade: JWST and Concurrent Facilities' (JWST Conference Proceedings), edited by H. A. Thronson, M. Stiavelli and A. G. G. M. Tielens; Springer Series: Astrophysics and Space Science Proceeding

Dust in Supernovae and Supernova Remnants I : Formation Scenarios

Supernovae are considered as prime sources of dust in space. Observations of local supernovae over the past couple of decades have detected the presence of dust in supernova ejecta. The reddening of the high redshift quasars also indicate the presence of large masses of dust in early galaxies. Considering the top heavy IMF in the early galaxies, supernovae are assumed to be the major contributor to these large amounts of dust. However, the composition and morphology of dust grains formed in a supernova ejecta is yet to be understood with clarity. Moreover, the dust masses inferred from observations in mid-infrared and submillimeter wavelength regimes differ by two orders of magnitude or more. Therefore, the mechanism responsible for the synthesis of molecules and dust in such environments plays a crucial role in studying the evolution of cosmic dust in galaxies. This review summarises our current knowledge of dust formation in supernova ejecta and tries to quantify the role of supernovae as dust producers in a galaxy.Peer reviewe