New records of the Paleotropical migrant Hemianax ephippiger in the Caribbean and a review of its status in the Neotropics

Tropical America is currently experiencing the establishment of a new apex insect predator, the Paleotropical dragonfly Hemianax ephippiger (Odonata: Aeshnidae). H. ephippiger is migratory and is suggested to have colonised the eastern Neotropics by chance Trans-Atlantic displacement. We report the discovery of H. ephippiger at three new locations in the Caribbean, the islands of Bonaire, Isla de Coche (Venezuela), and Martinique, and we review its reported distribution across the Neotropics. We discuss the establishment of H. ephippiger as a new apex insect predator in the Americas, both in terms of ecological implications and the possible provision of ecosystem services. We also provide an additional new species record for Bonaire, Pantala hymenaea (Odonata: Libellulidae).Peer reviewe

Radiation from the LTB black hole

Does a dynamical black hole embedded in a cosmological FRW background emit Hawking radiation where a globally defined event horizon does not exist? What are the differences to the Schwarzschild black hole? What about the first law of black hole mechanics? We face these questions using the LTB cosmological black hole model recently published. Using the Hamilton-Jacobi and radial null geodesic-methods suitable for dynamical cases, we show that it is the apparent horizon which contributes to the Hawking radiation and not the event horizon. The Hawking temperature is calculated using the two different methods giving the same result. The first law of LTB black hole dynamics and the thermal character of the radiation is also dealt with.Comment: 9 pages, revised version, Europhysics Letter 2012 97 2900

The genome sequence of the silver-studded blue, Plebejus argus (Linnaeus, 1758)

We present a genome assembly from an individual male Plebejus argus (silver-studded blue; Arthropoda; Insecta; Lepidoptera; Lycaenidae). The genome sequence is 382 megabases in span. The entire assembly (100%) is scaffolded into 23 chromosomal pseudomolecules with the Z sex chromosome assembled. The complete mitochondrial genome was also assembled and is 27.4 kilobases in length. Gene annotation of this assembly on Ensembl identified 12,693 protein coding genes.This work was supported by Wellcome through core funding to the Wellcome Sanger Institute (206194, https://doi.org/10.35802/206194) and the Darwin Tree of Life Discretionary Award (218328, https://doi.org/10.35802/218328). AH is supported by a Biotechnology and Biological Sciences Research Council (BBSRC) David Phillips Fellowship (BB/N020146/1). KL and DL are supported by an ERC grant (ModelGenomLand 757648) which also supported the fieldwork. KL was also supported by a NERC fellowship (NE/L011522/1). RV is supported by Grant PID2019-107078GB-I00 funded by Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación (MCIN/AEI/10.13039/ 501100011033).Peer reviewe

Doped Sr2FeIrO6 – phase separation and a Jeff ≠ 0 state for Ir5+

High-resolution synchrotron X-ray and neutron powder diffraction data demonstrate that, in contrast to recent reports, Sr2FeIrO6 adopts an I1 symmetry double perovskite structure with an a–b–c– tilting distortion. This distorted structure does not tolerate cation substitution, with low levels of A-site (Ca, Ba, La) or Fe-site (Ga) substitution leading to separation into two phases: a stoichiometric I1 phase and a cation-substituted, P21/n symmetry, a–a–c+ distorted double perovskite phase. Magnetization, neutron diffraction and 57Fe Mössbauer data show that in common with Sr2FeIrO6, the cation substituted Sr2-xAxFe1-yGayIrO6 phases undergo transitions to type-II antiferromagnetically ordered states at TN ~ 120 K. However, in contrast to stoichiometric Sr2FeIrO6, cation substituted samples exhibit a further magnetic transition at TA ~ 220 K, which corresponds to the ordering of reff ≠ 0 Ir5+ centers in the cation-substituted, P21/n symmetry, double perovskite phases

The effects of local stellar radiation and dust depletion on non-equilibrium interstellar chemistry

Interstellar chemistry is important for galaxy formation, as it determines the rate at which gas can cool, and enables us to make predictions for observable spectroscopic lines from ions and molecules. We explore two central aspects of modelling the chemistry of the interstellar medium (ISM): (1) the effects of local stellar radiation, which ionizes and heats the gas, and (2) the depletion of metals on to dust grains, which reduces the abundance of metals in the gas phase. We run high-resolution (400 M⊙ per baryonic particle) simulations of isolated disc galaxies, from dwarfs to Milky Way-mass, using the FIRE galaxy formation models together with the CHIMES non-equilibrium chemistry and cooling module. In our fiducial model, we couple the chemistry to the stellar fluxes calculated from star particles using an approximate radiative transfer scheme; and we implement an empirical density-dependent prescription for metal depletion. For comparison, we also run simulations with a spatially uniform radiation field, and without metal depletion. Our fiducial model broadly reproduces observed trends in H I and H2 mass with stellar mass, and in line luminosity versus star formation rate for [C II] 158μm , [O I] 63μm , [O III] 88μm , [N II] 122μm , and H α6563Å. Our simulations with a uniform radiation field predict fainter luminosities, by up to an order of magnitude for [O III] 88μm and H α6563Å, while ignoring metal depletion increases the luminosity of carbon and oxygen lines by a factor ~2. However, the overall evolution of the galaxy is not strongly affected by local stellar fluxes or metal depletion, except in dwarf galaxies where the inclusion of local fluxes leads to weaker outflows and hence higher gas fractions