Long Term Government Bonds

We study the impact of debt maturity on optimal fiscal policy by focusing on the case where the government issues a bond of maturity N > 1: Isolating these effects helps provide insight into the construction of optimal government debt portfolios. We find long bonds may not complete the market even in the absence of uncertainty, generate an incentive to twist interest rates and induce additional tax volatility compared to short term bonds. By focusing just on the issuance of long bonds we show that as well as their well known advantage in providing fiscal insurance long bonds also have less attractive features that induce additional tax volatility. In the case of long bonds, governments induce tax volatility in order to twist interest rates at maturity. This interest rate twisting effect is what makes optimal debt management models so difficult to solve computationally as the state space rapidly becomes cumbersome due to the need to keep track of promises about future tax rates. We provide an alternative institutional setup (\independent powers\) that eliminates this problem offering a simpler solution method. Introducing maturity requires making more institutional assumptions than is the case for one period bonds. In particular assumptions have to be made whether the government does or doesn't buy back each period all outstanding debt irrespective of maturity and whether long bonds pay coupons. This is important as the literature to date makes assumptions that are diametrically opposite to what is observed in practice. We show that this is an important divide as if we model optimal policy under the empirically motivated assumption that governments do not buyback bonds until maturity then long bonds induce additional tax volatility due to the existence of N period roll over cycles. These can be reduced in magnitude by the government issuing long bonds that pay coupons although because coupons reduce the duration of a bond below its maturity this does compromise the ability of long bonds to provide fiscal insurance

A Short Note on Optimal Debt Management under Asymmetric Information

We show that under asymetric information, if the government holds advanced information relative to the investors.some debt management policies may lead to bond market instability. The In particular, we show that the repurchase/reissuance strategy assumd in most of the current debt management literature would cause such a crisis and it would be therefore highly suboptimal.of a bond below its maturity this does compromise the ability of long bonds to provide fiscal insurance

Excitonic giant Zeeman effect in GaN:Mn^3+

We describe a direct observation of the excitonic giant Zeeman splitting in (Ga,Mn)N, a wide-gap III-V diluted magnetic semiconductor. Reflectivity and absorption spectra measured at low temperatures display the A and B excitons, with a shift under magnetic field due to s,p-d exchange interactions. Using an excitonic model, we determine the difference of exchange integrals between Mn^3+ and free carriers in GaN, N_0(alpha-beta)=-1.2 +/- 0.2 eV. Assuming a reasonable value of alpha, this implies a positive sign of beta which corresponds to a rarely observed ferromagnetic interaction between the magnetic ions and the holes.Comment: 4 pages, 4 figure

Ferromagnetic (Ga,Mn)N epilayers versus antiferromagnetic GaMn3_3N clusters

Mn-doped wurtzite GaN epilayers have been grown by nitrogen plasma-assisted molecular beam epitaxy. Correlated SIMS, structural and magnetic measurements show that the incorporation of Mn strongly depends on the conditions of the growth. Hysteresis loops which persist at high temperature do not appear to be correlated to the presence of Mn. Samples with up to 2% Mn are purely substitutional Ga$_{1-x}$Mn$_x$N epilayers, and exhibit paramagnetic properties. At higher Mn contents, precipitates are formed which are identified as GaMn$_3$N clusters by x-ray diffraction and absorption: this induces a decrease of the paramagnetic magnetisation. Samples co-doped with enough Mg exhibit a new feature: a ferromagnetic component is observed up to $T_c\sim175$ K, which cannot be related to superparamagnetism of unresolved magnetic precipitates.Comment: Revised versio

Authentication scheme for routine verification of genetically similar laboratory colonies: a trial with Anopheles gambiae

<p>Abstract</p> <p>Background</p> <p>When rearing morphologically indistinguishable laboratory strains concurrently, the threat of unintentional genetic contamination is constant. Avoidance of accidental mixing of strains is difficult due to the use of common equipment, technician error, or the possibility of self relocation by adult mosquitoes ("free fliers"). In many cases, laboratory strains are difficult to distinguish because of morphological and genetic similarity, especially when laboratory colonies are isolates of certain traits from the same parental strain, such as eye color mutants, individuals with certain chromosomal arrangements or high levels of insecticide resistance. Thus, proving genetic integrity could seem incredibly time-consuming or impossible. On the other hand, lacking proof of genetically isolated laboratory strains could question the validity of research results.</p> <p>Results</p> <p>We present a method for establishing authentication matrices to routinely distinguish and confirm that laboratory strains have not become physically or genetically mixed through contamination events in the laboratory. We show a specific example with application to <it>Anopheles gambiae sensu stricto </it>strains at the Malaria Research and Reference Reagent Resource Center. This authentication matrix is essentially a series of tests yielding a strain-specific combination of results.</p> <p>Conclusion</p> <p>These matrix-based methodologies are useful for several mosquito and insect populations but must be specifically tailored and altered for each laboratory based on the potential contaminants available at any given time. The desired resulting authentication plan would utilize the least amount of routine effort possible while ensuring the integrity of the strains.</p

Government Debt Management: The Long and the Short of It

Standard optimal Debt Management (DM) models prescribe a dominant role for long bonds and advocate against issuing short bonds. They require very large positions in order to complete markets and assume each period that governments repurchase all outstanding bonds and reissue (r/r) new ones. These features of DM are inconsistent with US data. We introduce incomplete markets via small transaction costs which serves to make optimal DM more closely resemble the data : r/r are negligible, short bond issuance substantial and persistent and short and long bonds positively co-vary. Intuitively long bonds help smooth taxes over states and short bonds over time. Solving incomplete market models with multiple assets is challenging so a further contribution of this paper is introducing a novel computational method to find global solutions

The Quest for Orthologs orthology benchmark service in 2022

The Orthology Benchmark Service (https://orthology.benchmarkservice.org) is the gold standard for orthology inference evaluation, supported and maintained by the Quest for Orthologs consortium. It is an essential resource to compare existing and new methods of orthology inference (the bedrock for many comparative genomics and phylogenetic analysis) over a standard dataset and through common procedures. The Quest for Orthologs Consortium is dedicated to maintaining the resource up to date, through regular updates of the Reference Proteomes and increasingly accessible data through the OpenEBench platform. For this update, we have added a new benchmark based on curated orthology assertion from the Vertebrate Gene Nomenclature Committee, and provided an example meta-analysis of the public predictions present on the platform.European Molecular Biology Laboratory (EMBL) (core funds to D.J. and M.J.M.); National Institutes of Health [U24HG007822 to D.J. and M.J.M., 75N93019C00077 to D.S.R.]; National Human Genome Research Institute (NHGRI) [U24HG003345 to T.E.M.J, B.Y., E.A.B.]; JSPS KAKENHI [16H06279, 19H05688 to W.I.]; JST CREST [JPMJCR19S2 to W.I.]; MEXT [JPMXD1521474594 to W.I.]; Horizon 2020 [676559 to S.C.-G., 637765] (to D.M.E.), ELIXIR (to S.C.-G.); Wellcome Grant [208349/Z/17/Z to E.A.B.]; National Science Foundation (USA) [1917302 to P.D.T.]; Wellcome Trust [WT-218288, WT-212929 to D.S.R.]; Service and Infrastructure grant from the Swiss Institute of Bioinformatics, Swiss National Science Foundation [186397, 205085 to C.D.]. Funding for open access charge: Swiss National Science Foundation [205085].Peer Reviewed"Article signat per 31 autors/es: Yannis Nevers, Tamsin E M Jones, Dushyanth Jyothi, Bethan Yates, Meritxell Ferret, Laura Portell-Silva, Laia Codo, Salvatore Cosentino, Marina Marcet-Houben, Anna Vlasova, Laetitia Poidevin, Arnaud Kress, Mark Hickman, Emma Persson, Ivana Piližota, Cristina Guijarro-Clarke, the OpenEBench team the Quest for Orthologs Consortium , Wataru Iwasaki, Odile Lecompte, Erik Sonnhammer, David S Roos, Toni Gabaldón, David Thybert, Paul D Thomas, Yanhui Hu, David M Emms, Elspeth Bruford, Salvador Capella-Gutierrez, Maria J Martin, Christophe Dessimoz, Adrian Altenhoff"Postprint (published version

Examination of Genome-Wide Ortholog variation in clinical and environmental isolates of the fungal pathogen Aspergillus fumigatus

Aspergillus fumigatus is a cosmopolitan species of fungus responsible for thousands of cases of invasive disease annually. Clinical and environmental isolates of A. fumigatus exhibit extensive phenotypic differences, including differences related to virulence and antifungal drug resistance. Aspergillus fumigatus is both an environmental saprobe and an opportunistic human fungal pathogen. Knowledge of genomic variation across A. fumigatus isolates is essential for understanding the evolution of pathogenicity, virulence, and resistance to antifungal drugs. Here, we investigated 206 A. fumigatus isolates (133 clinical and 73 environmental isolates), aiming to identify genes with variable presence across isolates and test whether this variation was related to the clinical or environmental origin of isolates. The PanOrtho genome of A. fumigatus consists of 13,085 ortholog groups, of which 7,773 (59.4\%) are shared by all isolates (core groups) and 5,312 (40.6\%) vary in their gene presence across isolates (accessory groups plus singletons). Despite differences in the distribution of orthologs across all isolates, no significant differences were observed among clinical versus environmental isolates when phylogeny was accounted for. Orthologs that differ in their distribution across isolates tend to occur at low frequency and/or be restricted to specific isolates; thus, the degree of genomic conservation between orthologs of A. fumigatus is high. These results suggest that differences in the distribution of orthologs within A. fumigatus cannot be associated with the clinical or environmental origin of isolates. IMPORTANCE Aspergillus fumigatus is a cosmopolitan species of fungus responsible for thousands of cases of invasive disease annually. Clinical and environmental isolates of A. fumigatus exhibit extensive phenotypic differences, including differences related to virulence and antifungal drug resistance. A comprehensive survey of the genomic diversity present in A. fumigatus and its relationship to the clinical or environmental origin of isolates can contribute to the prediction of the mechanisms of evolution and infection of the species. Our results suggest that there is no significant variation in ortholog distribution between clinical and environmental isolates when accounting for evolutionary history. The work supports the hypothesis that environmental and clinical isolates of A. fumigatus do not differ in their gene contents.We thank Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) 2020/10536-9 (M.A.C.H.) and 2016/07870-9 (G.H.G.) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) 301058/2019-9 and 404735/2018-5 (G.H.G.), both in Brazil, and National Institutes of Health/National Institute of Allergy and Infectious Diseases (R01AI153356) (A.R. and G.H.G.), in the United States.Peer ReviewedPostprint (published version