The size and shape of the Milky Way disc and halo from M-type brown dwarfs in the BoRG survey.

We have identified 274 M-type brown dwarfs in the Hubble Space Telescope\u27s Wide Field Camera 3 pure parallel fields from the Brightest of Reionizing Galaxies (BoRG) survey for high-redshift galaxies. These are near-infrared observations with multiple lines of sight out of our Milky Way. Using these observed M-type brown dwarfs, we fitted a Galactic disc and halo model with a Markov chain Monte Carlo analysis. This model worked best with the scalelength of the disc fixed at h = 2.6 kpc. For the scaleheight of the disc, we found z0=0.29+0.02−0.019 z0=0.29−0.019+0.02 kpc and for the central number density, ρ0=0.29+0.20−0.13 ρ0=0.29−0.13+0.20 # pc−3. For the halo, we derived a flattening parameter κ = 0.45 ± 0.04 and a power-law index p = 2.4 ± 0.07. We found the fraction of M-type brown dwarfs in the local density that belong to the halo to be fh = 0.0075 +0.0025−0.0019 −0.0019+0.0025 . We found no correlation between subtype of M-dwarf and any model parameters. The total number of M-type brown dwarfs in the disc and halo was determined to be 58.2+9.81−6.70×109 58.2−6.70+9.81×109 . We found an upper limit for the fraction of M-type brown dwarfs in the halo of 7 +5−4 −4+5  per cent. The upper limit for the total Galactic disc mass in M-dwarfs is 4.34+0.73−0.5×109 4.34−0.5+0.73×109 M⊙, assuming all M-type brown dwarfs have a mass of 80 MJ

Electronically Asynchronous Transition States for C-N Bond Formation by Electrophilic [Co-^III(TAML)]-Nitrene Radical Complexes Involving Substrate-to-Ligand Single-Electron Transfer and a Cobalt-Centered Spin Shuttle

[Image: see text] The oxidation state of the redox noninnocent tetra-amido macrocyclic ligand (TAML) scaffold was recently shown to affect the formation of nitrene radical species on cobalt(III) upon reaction with PhI=NNs [ N. P. van Leest; J. Am. Chem. Soc.2020, 142, 552−56331846578]. For the neutral [Co(III)(TAML(sq))] complex, this leads to the doublet (S = 1/2) mono-nitrene radical species [Co(III)(TAML(q))(N(•)Ns)(Y)] (bearing an unidentified sixth ligand Y in at least the frozen state), while a triplet (S = 1) bis-nitrene radical species [Co(III)(TAML(q))(N(•)Ns)(2)](–) is generated from the anionic [Co(III)(TAML(red))](–) complex. The one-electron-reduced Fischer-type nitrene radicals (N(•)Ns(–)) are formed through single (mono-nitrene) or double (bis-nitrene) ligand-to-substrate single-electron transfer (SET). In this work, we describe the reactivity and mechanisms of these nitrene radical complexes in catalytic aziridination. We report that [Co(III)(TAML(sq))] and [Co(III)(TAML(red))](–) are both effective catalysts for chemoselective (C=C versus C–H bonds) and diastereoselective aziridination of styrene derivatives, cyclohexane, and 1-hexene under mild and even aerobic (for [Co(III)(TAML(red))](–)) conditions. Experimental (Hammett plots; [Co(III)(TAML)]-nitrene radical formation and quantification under catalytic conditions; single-turnover experiments; and tests regarding catalyst decomposition, radical inhibition, and radical trapping) in combination with computational (density functional theory (DFT), N-electron valence state perturbation theory corrected complete active space self-consistent field (NEVPT2-CASSCF)) studies reveal that [Co(III)(TAML(q))(N(•)Ns)(Y)], [Co(III)(TAML(q))(N(•)Ns)(2)](–), and [Co(III)(TAML(sq))(N(•)Ns)](–) are key electrophilic intermediates in aziridination reactions. Surprisingly, the electrophilic one-electron-reduced Fischer-type nitrene radicals do not react as would be expected for nitrene radicals (i.e., via radical addition and radical rebound). Instead, nitrene transfer proceeds through unusual electronically asynchronous transition states, in which the (partial) styrene substrate to TAML ligand (single-) electron transfer precedes C–N coupling. The actual C–N bond formation processes are best described as involving a nucleophilic attack of the nitrene (radical) lone pair at the thus (partially) formed styrene radical cation. These processes are coupled to TAML-to-cobalt and cobalt-to-nitrene single-electron transfer, effectively leading to the formation of an amido-γ-benzyl radical (NsN(–)–CH(2)–(•)CH–Ph) bound to an intermediate spin (S = 1) cobalt(III) center. Hence, the TAML moiety can be regarded to act as a transient electron acceptor, the cobalt center behaves as a spin shuttle, and the nitrene radical acts as a nucleophile. Such a mechanism was hitherto unknown for cobalt-catalyzed hypovalent group transfer and the more general transition-metal-catalyzed nitrene transfer to alkenes but is now shown to complement the known concerted and stepwise mechanisms for N-group transfer

Multiplex-detectie van plantenpathogenen

Een manier om de kosteneffectiviteit van de detectie van plantenpathogenen te verbeteren is door het tegelijkertijd detecteren van meerdere pathogenen in één monster (zgn. multiplexen). Het gebruik van de Luminex xMAP-technologie biedt een uitgelezen platform om bestaande reagentia in te zetten in een multiplex-setting

Identification and characterisation of tomato torrado virus, a new plant picorna-like virus from tomato

A new virus was isolated from tomato plants from the Murcia region in Spain which showed symptoms of ‘torrado disease’ very distinct necrotic, almost burn-like symptoms on leaves of infected plants. The virus particles are isometric with a diameter of approximately 28 nm. The viral genome consists of two (+)ssRNA molecules of 7793 (RNA1) and 5389 nts (RNA2). RNA1 contains one open reading frame (ORF) encoding a predicted polyprotein of 241 kDa that shows conserved regions with motifs typical for a protease-cofactor, a helicase, a protease and an RNA-dependent RNA polymerase. RNA2 contains two, partially overlapping ORFs potentially encoding proteins of 20 and 134 kDa. These viral RNAs are encapsidated by three proteins with estimated sizes of 35, 26 and 23 kDa. Direct protein sequencing mapped these coat proteins to ORF2 on RNA2. Phylogenetic analyses of nucleotide and derived amino acid sequences showed that the virus is related to but distinct from viruses belonging to the genera Sequivirus, Sadwavirus and Cheravirus. This new virus, for which the name tomato torrado virus is proposed, most likely represents a member of a new plant virus genus

Complete Solving for Explicit Evaluation of Gauss Sums in the Index 2 Case

Let $p$ be a prime number, $q=p^f$ for some positive integer $f$, $N$ be a positive integer such that $\gcd(N,p)=1$, and let \k be a primitive multiplicative character of order $N$ over finite field \fq. This paper studies the problem of explicit evaluation of Gauss sums in "\textsl{index 2 case}" (i.e. f=\f{\p(N)}{2}=[\zn:\pp], where \p(\cd) is Euler function). Firstly, the classification of the Gauss sums in index 2 case is presented. Then, the explicit evaluation of Gauss sums G(\k^\la) (1\laN-1) in index 2 case with order $N$ being general even integer (i.e. N=2^{r}\cd N_0 where $r,N_0$ are positive integers and $N_03$ is odd.) is obtained. Thus, the problem of explicit evaluation of Gauss sums in index 2 case is completely solved

The very long-term risk and predictors of recurrent ischaemic events after a stroke at a young age: The FUTURE study.

INTRODUCTION: Patients who suffer a stroke at a young age, remain at a substantial risk of developing recurrent vascular events and information on very long-term prognosis and its risk factors is indispensable. Our aim is to investigate this very long-term risk and associated risk factors up to 35 years after stroke. PATIENTS AND METHODS: Prospective cohort study among 656 patients with a first-ever ischaemic stroke or transient ischaemic stroke (TIA), aged 18-50, who visited our hospital (1980-2010). Outcomes assessed at follow-up (2014-2015) included TIA or ischaemic stroke and other arterial events, whichever occurred first. Kaplan-Meier analysis quantified cumulative risks. A prediction model was constructed to assess risk factors independently associated with any ischaemic event using Cox proportional hazard analyses followed by bootstrap validation procedure to avoid overestimation. RESULTS: Mean follow-up was 12.4 (SD 8.2) years (8105 person-years). Twenty-five years cumulative risk was 45.4% (95%CI: 39.4-51.5) for any ischaemic event, 30.1% (95%CI: 24.8-35.4) for cerebral ischaemia and 27.0% (95%CI: 21.1-33.0) for other arterial events. Risk factors retained in the prediction model were smoking (HR 1.35, 95%CI: 1.04-1.74), poor kidney function (HR 2.10, 95%CI: 1.32-3.35), history of peripheral arterial disease (HR 2.10, 95%CI: 1.08-3.76) and cardiac disease (HR 1.84, 95%CI: 1.06-3.18) (C-statistic 0.59 (95%CI: 0.55-0.64)). DISCUSSION AND CONCLUSION: Young stroke patients remain at a substantial risk for recurrent events; almost 1 of 2 develops a recurrent ischaemic event and 1 of 3 develops a recurrent stroke or TIA during 25 years of follow-up. Risk factors independently associated with recurrent events were poor kidney function, smoking, history of peripheral arterial disease and cardiac disease.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Frank-Erik de Leeuw received research support from the ‘‘Dutch Epilepsy Fund’’ (grant number 2010-18), ‘Dutch Heart Foundation’ (clinical established investigator grant, grant number 2014-T060) and ‘‘The Dutch Organisation for Health Research and Development’’ (VIDI innovational grant, ZonMw, grant number 016-126-351). Loes Rutten- Jacobs was supported by a British Heart Foundation Immediate Research Fellowship (FS/15/61/31626) (www. bhf.org.uk).This is the author accepted manuscript. The final version is available from SAGE Publications via https://doi.org/10.1177/239698731667344

Erratum: “Milky Way red dwarfs in the Borg survey; galactic scale-height and the distribution of dwarfs stars in WFC3 imaging .

In the catalog of M-dwarfs presented in Holwerda et al. (2014, H14 hereafter), there is an issue with the conversion from celestial coordinates to Galactic ones, done with PYEPHEM a wrapper around a trusted and vetted library ephermis. Here we present the corrected coordinates (using ASTROPY) and distances based on AB magnitudes. We have amended the tables and figures accordingly. The relation between vertical scale-height (z0) and M- dwarf subtype found in H14 is no longer present. We find a scale-height of 600 pc for all types, in part due to the presence of a second Galactic structural component