Hydrodynamics of embedded planets' first atmospheres - III. The role of radiation transport for super-Earth planets

The population of close-in super-Earths, with gas mass fractions of up to 10% represents a challenge for planet formation theory: how did they avoid runaway gas accretion and collapsing to hot Jupiters despite their core masses being in the critical range of $M_\mathrm{c} \simeq 10 M_\mathrm{\oplus}$? Previous three-dimensional (3D) hydrodynamical simulations indicate that atmospheres of low-mass planets cannot be considered isolated from the protoplanetary disc, contrary to what is assumed in 1D-evolutionary calculations. This finding is referred to as the recycling hypothesis. In this Paper we investigate the recycling hypothesis for super-Earth planets, accounting for realistic 3D radiation hydrodynamics. Also, we conduct a direct comparison in terms of the evolution of the entropy between 1D and 3D geometries. We clearly see that 3D atmospheres maintain higher entropy: although gas in the atmosphere loses entropy through radiative cooling, the advection of high entropy gas from the disc into the Bondi/Hill sphere slows down Kelvin-Helmholtz contraction, potentially arresting envelope growth at a sub-critical gas mass fraction. Recycling, therefore, operates vigorously, in line with results by previous studies. However, we also identify an "inner core" -- in size $\approx$ 25% of the Bondi radius -- where streamlines are more circular and entropies are much lower than in the outer atmosphere. Future studies at higher resolutions are needed to assess whether this region can become hydrodynamically-isolated on long time-scales.Comment: 16 pages, 12 figures, accepted for publication at MNRA

Torque wiggles -- a robust feature of the global disc-planet interaction

Gravitational coupling between planets and protoplanetary discs is responsible for many important phenomena such as planet migration and gap formation. The key quantitative characteristics of this coupling is the excitation torque density -- the torque (per unit radius) imparted on the disc by planetary gravity. Recent global simulations and linear calculations found an intricate pattern of low-amplitude, quasi-periodic oscillations in the global radial distribution of torque density in the outer disc, which we call torque wiggles. Here we show that torque wiggles are a robust outcome of global disc-planet interaction and exist despite the variation of disc parameters and thermodynamic assumptions (including $\beta$-cooling). They result from coupling of the planetary potential to the planet-driven density wave freely propagating in the disc. We developed analytical theory of this phenomenon based on approximate self-similarity of the planet-driven density waves in the outer disc. We used it, together with linear calculations and simulations, to show that (a) the radial periodicity of the wiggles is determined by the global shape of the planet-driven density wave (its wrapping in the disc) and (b) the sharp features in the torque density distribution result from constructive interference of different azimuthal (Fourier) torque contributions at radii where the planetary wake crosses the star-planet line. In the linear regime the torque wiggles represent a weak effect, affecting the total (integrated) torque by only a few per cent. However, their significance should increase in the non-linear regime, when a gap (or a cavity) forms around the perturber's orbit.Comment: 19 pages, 15 figures, submitted to MNRA

HMG-CoA reductase is regulated by environmental salinity and its activity is essential for halotolerance in halophilic fungi

The activity and level of HMG-CoA reductase (HMGR) were addressed in halophilic fungi isolated from solar saltpans. Representative fungi belonging to the orders Dothideales, Eurotiales and Wallemiales have a specific pattern of HMGR regulation, which differs from salt-sensitive and moderately salt-tolerant yeasts. In all of the halophilic fungi studied, HMGR amounts and activities were the lowest at optimal growth salinity and increased under hyposaline and hypersaline conditions. This profile paralleled isoprenylation of cellular proteins in H. werneckii. Inhibition of HMGR in vivo by lovastatin impaired the halotolerant character. HMGR may thus serve as an important molecular marker of halotolerance

Redefinition of Aureobasidium pullulans and its varieties

Using media with low water activity, a large numbers of aureobasidium-like black yeasts were isolated from glacial and subglacial ice of three polythermal glaciers from the coastal Arctic environment of Kongsfjorden (Svalbard, Spitsbergen), as well as from adjacent sea water, sea ice and glacial meltwaters. To characterise the genetic variability of Aureobasidium pullulans strains originating from the Arctic and strains originating pan-globally, a multilocus molecular analysis was performed, through rDNA (internal transcribed spacers, partial 28 S rDNA), and partial introns and exons of genes encoding β-tubulin (TUB), translation elongation factor (EF1α) and elongase (ELO). Two globally ubiquitous varieties were distinguished: var. pullulans, occurring particularly in slightly osmotic substrates and in the phyllosphere; and var. melanogenum, mainly isolated from watery habitats. Both varieties were commonly isolated from the sampled Arctic habitats. However, some aureobasidium-like strains from subglacial ice from three different glaciers in Kongsfjorden (Svalbard, Spitsbergen), appeared to represent a new variety of A. pullulans. A strain from dolomitic marble in Namibia was found to belong to yet another variety. No molecular support has as yet been found for the previously described var. aubasidani. A partial elongase-encoding gene was successfully used as a phylogenetic marker at the (infra-)specific level

Antihyperlipidemic effects of Pleurotus ostreatus (oyster mushrooms) in HIV-infected individuals taking antiretroviral therapy

<p>Abstract</p> <p>Background</p> <p>Antiretroviral treatment (ART) regimens in HIV patients commonly cause significant lipid elevations, including increases in both triglycerides and cholesterol. Standard treatments for hypercholesterolemia include the HMG CoA reductase inhibitors, or "statins." Because many ART agents and statins share a common metabolic pathway that uses the cytochrome P450 enzyme system, coadministration of ART with statins could increase statin plasma levels significantly. The oyster mushroom, <it>Pleurotus ostreatus</it>, has been shown in animal models to decrease lipid levels - a finding that has been supported by preliminary data in a small human trial.</p> <p>Methods</p> <p>To assess the safety and efficacy of <it>P. ostreatus </it>in patients with HIV and ART-induced hyperlipidemia, a single-arm, open-label, proof-of-concept study of 8 weeks' duration with a target enrollment of 20 subjects was conducted. Study patients with ART-induced elevated non-HDL cholesterol levels (> 160 mg/dL) were enrolled. Participants received packets of freeze-dried <it>P. ostreatus </it>(15 gm/day) to be administered orally for the 8 week trial period. Lipid levels were drawn every two weeks to assess efficacy. Safety assessments included self-reported incidence of muscle aches and measurement of liver and muscle enzymes. Mean within-person change in lipid levels were estimated using generalized estimating equations to account for repeated observations on individuals. A 30 mg/dL decrease in non-HDL cholesterol was deemed clinically significant.</p> <p>Results</p> <p>126 patients were screened to enroll 25, of which 20 completed the 8-week study. The mean age was 46.4 years (36-60). Patients had a mean 13.7 yrs of HIV infection. Mean non-HDL cholesterol was 204.5 mg/dL at day 0 and 200.2 mg/dL at day 56 (mean within-person change = -1.70; 95% confidence interval (CI) = -17.4, 14.0). HDL cholesterol levels increased from 37.8 mg/dL at day 0 to 40.4 mg/dL on day 56 (mean within-person change = 2.6; 95% CI = -0.1, 5.2). Triglycerides dropped from 336.4 mg/dL on day 0 to 273.4 mg/dL on day 56 (mean within-person change = -63.0; 95% CI = -120.9, -5.1). Only 3 individuals achieved a sustained clinically significant (30 mg/dL) decline in non-HDL cholesterol after 8 weeks of therapy. There were no adverse experiences reported other than patients' distaste for the preparation. Liver function tests and muscle enzymes were not affected by the 8 weeks of treatment.</p> <p>Conclusions</p> <p><it>Pleurotus ostreatus </it>as administered in this experiment did not lower non-HDL cholesterol in HIV patients with ART-induced hypercholesterolemia. Small changes in HDL and triglycerides were not of a clinical magnitude to warrant further study.</p> <p>Trial Registration</p> <p>clinicaltrials.gov Identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00069524">NCT00069524</a></p

Heliyon

Purpose: Restraint is often used when administering procedures to children. However, no metrologically scale to measure the restraint intensity had yet been validated. This study validated the metrological criteria of a scale measuring the restraint intensity, Procedural Restraint Intensity in Children (PRIC), used during procedures in children. Design and methods: The PRIC scale performance was measured by a group of 7 health professionals working in a children's hospital, by watching 20 videos of health care procedures. This group included 2 physicians, 1 pediatric resident, and 4 nurses. The intra-class correlation coefficients were calculated to evaluate the inter-rater and test-retest reliability and the construct validity with the correlation between PRIC scale and a numerical rating scale. Results: One hundred and forty measurements were made. Inter-rater and test-retest correlation coefficients were 0.98 and 0.98, respectively. The 2 scales were positively correlated with a Spearman coefficient of 0.93. Conclusions: This study validated the Procedural Restraint Intensity in Children (PRIC) scale in metrological terms with some limitation. However, there is not gold standard scale to precisely validate the reliability of this tool and this study has been conducted in "experimental" conditions. Nevertheless, this is the first scale measuring the intensity of physical restraint with a metrological validation. The next step will be to validate it in real clinical situations

Across the tree of life, radiation resistance is governed by antioxidant Mn2+, gauged by paramagnetic resonance

Despite concerted functional genomic efforts to understand the complex phenotype of ionizing radiation (IR) resistance, a genome sequence cannot predict whether a cell is IR-resistant or not. Instead, we report that absorption-display electron paramagnetic resonance (EPR) spectroscopy of nonirradiated cells is highly diagnostic of IR survival and repair efficiency of DNA double-strand breaks (DSBs) caused by exposure to gamma radiation across archaea, bacteria, and eukaryotes, including fungi and human cells. IR-resistant cells, which are efficient at DSB repair, contain a high cellular content of manganous ions (Mn2+) in high-symmetry (H) antioxidant complexes with small metabolites (e.g., orthophosphate, peptides), which exhibit narrow EPR signals (small zero-field splitting). In contrast, Mn2+ ions in IR-sensitive cells, which are inefficient at DSB repair, exist largely as low-symmetry (L) complexes with substantially broadened spectra seen with enzymes and strongly chelating ligands. The fraction of cellular Mn2+ present as H-complexes (H-Mn2+), as measured by EPR of live, nonirradiated Mn-replete cells, is now the strongest known gauge of biological IR resistance between and within organisms representing all three domains of life: Antioxidant H-Mn2+ complexes, not antioxidant enzymes (e.g., Mn superoxide dismutase), govern IR survival. As the pool of intracellular metabolites needed to form H-Mn2+ complexes depends on the nutritional status of the cell, we conclude that IR resistance is predominantly a metabolic phenomenon. In a cross-kingdom analysis, the vast differences in taxonomic classification, genome size, and radioresistance between cell types studied here support that IR resistance is not controlled by the repertoire of DNA repair and antioxidant enzymes

Phylogeny and ecology of the ubiquitous saprobe Cladosporium sphaerospermum, with descriptions of seven new species from hypersaline environments

Saprobic Cladosporium isolates morphologically similar to C. sphaerospermum are phylogenetically analysed on the basis of DNA sequences of the ribosomal RNA gene cluster, including the internal transcribed spacer regions ITS1 and ITS2, the 5.8S rDNA (ITS) and the small subunit (SSU) rDNA as well as β-tubulin and actin gene introns and exons. Most of the C. sphaerospermum-like species show halotolerance as a recurrent feature. Cladosporium sphaerospermum, which is characterised by almost globose conidia, is redefined on the basis of its ex-neotype culture. Cladosporium dominicanum, C. psychrotolerans, C. velox, C. spinulosum and C. halotolerans, all with globoid conidia, are newly described on the basis of phylogenetic analyses and cryptic morphological and physiological characters. Cladosporium halotolerans was isolated from hypersaline water and bathrooms and detected once on dolphin skin. Cladosporium dominicanum and C. velox were isolated from plant material and hypersaline water. Cladosporium psychrotolerans, which grows well at 4 °C but not at 30 °C, and C. spinulosum, having conspicuously ornamented conidia with long digitate projections, are currently only known from hypersaline water. We also newly describe C. salinae from hypersaline water and C. fusiforme from hypersaline water and animal feed. Both species have ovoid to ellipsoid conidia and are therefore reminiscent of C. herbarum. Cladosporium langeronii (= Hormodendrum langeronii) previously described as a pathogen on human skin, is halotolerant but has not yet been recorded from hypersaline environments

Planetary population synthesis

In stellar astrophysics, the technique of population synthesis has been successfully used for several decades. For planets, it is in contrast still a young method which only became important in recent years because of the rapid increase of the number of known extrasolar planets, and the associated growth of statistical observational constraints. With planetary population synthesis, the theory of planet formation and evolution can be put to the test against these constraints. In this review of planetary population synthesis, we first briefly list key observational constraints. Then, the work flow in the method and its two main components are presented, namely global end-to-end models that predict planetary system properties directly from protoplanetary disk properties and probability distributions for these initial conditions. An overview of various population synthesis models in the literature is given. The sub-models for the physical processes considered in global models are described: the evolution of the protoplanetary disk, the planets' accretion of solids and gas, orbital migration, and N-body interactions among concurrently growing protoplanets. Next, typical population synthesis results are illustrated in the form of new syntheses obtained with the latest generation of the Bern model. Planetary formation tracks, the distribution of planets in the mass-distance and radius-distance plane, the planetary mass function, and the distributions of planetary radii, semimajor axes, and luminosities are shown, linked to underlying physical processes, and compared with their observational counterparts. We finish by highlighting the most important predictions made by population synthesis models and discuss the lessons learned from these predictions - both those later observationally confirmed and those rejected.Comment: 47 pages, 12 figures. Invited review accepted for publication in the 'Handbook of Exoplanets', planet formation section, section editor: Ralph Pudritz, Springer reference works, Juan Antonio Belmonte and Hans Deeg, Ed