Numerical solution of a non-linear conservation law applicable to the interior dynamics of partially molten planets

The energy balance of a partially molten rocky planet can be expressed as a non-linear diffusion equation using mixing length theory to quantify heat transport by both convection and mixing of the melt and solid phases. In this formulation the effective or eddy diffusivity depends on the entropy gradient, $\partial S/\partial r$, as well as entropy. First we present a simplified model with semi-analytical solutions, highlighting the large dynamic range of $\partial S/\partial r$, around 12 orders of magnitude, for physically-relevant parameters. It also elucidates the thermal structure of a magma ocean during the earliest stage of crystal formation. This motivates the development of a simple, stable numerical scheme able to capture the large dynamic range of $\partial S/\partial r$ and provide a flexible and robust method for time-integrating the energy equation. We then consider a full model including energy fluxes associated with convection, mixing, gravitational separation, and conduction that all depend on the thermophysical properties of the melt and solid phases. This model is discretised and evolved by applying the finite volume method (FVM), allowing for extended precision calculations and using $\partial S/\partial r$ as the solution variable. The FVM is well-suited to this problem since it is naturally energy conserving, flexible, and intuitive to incorporate arbitrary non-linear fluxes that rely on lookup data. Special attention is given to the numerically challenging scenario in which crystals first form in the centre of a magma ocean. Our computational framework is immediately applicable to modelling high melt fraction phenomena in Earth and planetary science research. Furthermore, it provides a template for solving similar non-linear diffusion equations arising in other disciplines, particularly for non-linear functional forms of the diffusion coefficient

Linking the evolution of terrestrial interiors and an early outgassed atmosphere to astrophysical observations

A terrestrial planet is molten during formation and may remain so if subject to intense insolation or tidal forces. Observations continue to favour the detection and characterisation of hot planets, potentially with large outgassed atmospheres. We aim to determine the radius of hot Earth-like planets with large outgassed atmospheres and explore differences between molten and solid silicate planets and their influence on the mass-radius relationship and transmission and emission spectra. An interior-atmosphere model, combined with static structure calculations, tracks the evolving radius of a rocky mantle that is outgassing CO$_2$ and H$_2$O. Synthetic emission and transmission spectra are generated for CO$_2$ and H$_2$O dominated atmospheres. Atmospheres dominated by CO$_2$ suppress the outgassing of H$_2$O to a greater extent than previously realised, as previous studies have applied an erroneous relationship between volatile mass and partial pressure. We therefore predict more H$_2$O can be retained by the interior during the later stages of magma ocean crystallisation. Furthermore, formation of a lid at the surface can tie outgassing of H$_2$O to the efficiency of heat transport through the lid, rather than the atmosphere's radiative timescale. Contraction of the mantle as it solidifies gives $\sim5\%$ radius decrease, which can partly be offset by addition of a relatively light species to the atmosphere. We conclude that a molten silicate mantle can increase the radius of a terrestrial planet by around $5\%$ compared to its solid counterpart, or equivalently account for a $13\%$ decrease in bulk density. An outgassing atmosphere can perturb the total radius according to its speciation. Atmospheres of terrestrial planets around M-stars that are dominated by CO$_2$ or H$_2$O can be distinguished by observing facilities with extended wavelength coverage (e.g., JWST).Comment: 19 pages, published in A&A, abstract shortene

Dark matter in archaeal genomes: a rich source of novel mobile elements, defense systems and secretory complexes

International audienceMicrobial genomes encompass a sizable fraction of poorly characterized, narrowly spread fast-evolving genes. Using sensitive methods for sequences comparison and protein structure prediction, we performed a detailed comparative analysis of clusters of such genes, which we denote "dark matter islands", in archaeal genomes. The dark matter islands comprise up to 20% of archaeal genomes and show remarkable heterogeneity and diversity. Nevertheless, three classes of entities are common in these genomic loci: (a) integrated viral genomes and other mobile elements; (b) defense systems, and (c) secretory and other membrane-associated systems. The dark matter islands in the genome of thermophiles and mesophiles show similar general trends of gene content, but thermophiles are substantially enriched in predicted membrane proteins whereas mesophiles have a greater proportion of recognizable mobile elements. Based on this analysis, we predict the existence of several novel groups of viruses and mobile elements, previously unnoticed variants of CRISPR-Cas immune systems, and new secretory systems that might be involved in stress response, intermicrobial conflicts and biogenesis of novel, uncharacterized membrane structures

SkyMapper Southern Survey: First Data Release (DR1)

We present the first data release (DR1) of the SkyMapper Southern Survey, a hemispheric survey carried out with the SkyMapper Telescope at Siding Spring Observatory in Australia. Here, we present the survey strategy, data processing, catalogue construction and database schema. The DR1 dataset includes over 66,000 images from the Shallow Survey component, covering an area of 17,200 deg$^2$ in all six SkyMapper passbands $uvgriz$, while the full area covered by any passband exceeds 20,000 deg$^2$. The catalogues contain over 285 million unique astrophysical objects, complete to roughly 18 mag in all bands. We compare our $griz$ point-source photometry with PanSTARRS1 DR1 and note an RMS scatter of 2%. The internal reproducibility of SkyMapper photometry is on the order of 1%. Astrometric precision is better than 0.2 arcsec based on comparison with Gaia DR1. We describe the end-user database, through which data are presented to the world community, and provide some illustrative science queries.Comment: 31 pages, 19 figures, 10 tables, PASA, accepte

Size rather than complexity of sexual ornaments prolongs male metamorphosis and explains sexual size dimorphism in sepsid flies

Male sexual ornaments often evolve rapidly and are thought to be costly, thus contributing to sexual size dimorphism. However, little is known about their developmental costs, and even less about costs associated with structural complexity. Here, we quantified the size and complexity of three morphologically elaborate sexually dimorphic male ornaments that starkly differ across sepsid fly species (Diptera: Sepsidae): (i) male forelegs range from being unmodified, like in most females, to being adorned with spines and large cuticular protrusions; (ii) the fourth abdominal sternites are either unmodified or are converted into complex de novo appendages; and (iii) male genital claspers range from small and simple to large and complex (e.g. bifurcated). We tracked the development of 18 sepsid species from egg to adult to determine larval feeding and pupal metamorphosis times of both sexes. We then statistically explored whether pupal and adult body size, ornament size and/or ornament complexity are correlated with sex-specific development times. Larval growth and foraging periods of male and female larvae did not differ, but the time spent in the pupal stage was ca 5% longer for sepsid males despite emerging 9% smaller than females on average. Surprisingly, we found no evidence that sexual trait complexity prolongs pupal development beyond some effects of trait size. Evolving more complex traits thus does not incur developmental costs at least in this system

In vivo Recording Quality of Mechanically Decoupled Floating Versus Skull-Fixed Silicon-Based Neural Probes

Throughout the past decade, silicon-based neural probes have become a driving force in neural engineering. Such probes comprise sophisticated, integrated CMOS electronics which provide a large number of recording sites along slender probe shanks. Using such neural probes in a chronic setting often requires them to be mechanically anchored with respect to the skull. However, any relative motion between brain and implant causes recording instabilities and tissue responses such as glial scarring, thereby shielding recordable neurons from the recording sites integrated on the probe and thus decreasing the signal quality. In the current work, we present a comparison of results obtained using mechanically fixed and floating silicon neural probes chronically implanted into the cortex of a non-human primate. We demonstrate that the neural signal quality estimated by the quality of the spiking and local field potential (LFP) recordings over time is initially superior for the floating probe compared to the fixed device. Nonetheless, the skull-fixed probe also allowed long-term recording of multi-unit activity (MUA) and low frequency signals over several months, especially once pulsations of the brain were properly controlled

The Star Formation and Extinction Co-Evolution of UV-Selected Galaxies over 0.05<z<1.2

We use a new stacking technique to obtain mean mid IR and far IR to far UV flux ratios over the rest near-UV/near-IR color-magnitude diagram. We employ COMBO-17 redshifts and COMBO-17 optical, GALEX far and near UV, Spitzer IRAC and MIPS Mid IR photometry. This technique permits us to probe infrared excess (IRX), the ratio of far IR to far UV luminosity, and specific star formation rate (SSFR) and their co-evolution over two orders of magnitude of stellar mass and redshift 0.1<z<1.2. We find that the SSFR and the characteristic mass (M_0) above which the SSFR drops increase with redshift (downsizing). At any given epoch, IRX is an increasing function of mass up to M_0. Above this mass IRX falls, suggesting gas exhaustion. In a given mass bin below M_0 IRX increases with time in a fashion consistent with enrichment. We interpret these trends using a simple model with a Schmidt-Kennicutt law and extinction that tracks gas density and enrichment. We find that the average IRX and SSFR follows a galaxy age parameter which is determined mainly by the galaxy mass and time since formation. We conclude that blue sequence galaxies have properties which show simple, systematic trends with mass and time such as the steady build-up of heavy elements in the interstellar media of evolving galaxies and the exhaustion of gas in galaxies that are evolving off the blue sequence. The IRX represents a tool for selecting galaxies at various stages of evolution.Comment: Accepted for publication in GALEX Special Ap.J.Suppl., December, 200

A systematic review of the neural correlates of sexual minority stress: towards an intersectional minority mosaic framework with implications for a future research agenda

Background: Systemic oppression, particularly towards sexual minorities, continues to be deeply rooted in the bedrock of many societies globally. Experiences with minority stressors (e.g. discrimination, hate-crimes, internalized homonegativity, rejection sensitivity, and microaggressions or everyday indignities) have been consistently linked to adverse mental health outcomes. Elucidating the neural adaptations associated with minority stress exposure will be critical for furthering our understanding of how sexual minorities become disproportionately affected by mental health burdens. Following PRISMA-guidelines, we systematically reviewed published neuroimaging studies that compared neural dynamics among sexual minority and heterosexual populations, aggregating information pertaining to any measurement of minority stress and relevant clinical phenomena. Results: Only 1 of 13 studies eligible for inclusion examined minority stress directly, where all other studies focused on investigating the neurobiological basis of sexual orientation. In our narrative synthesis, we highlight important themes that suggest minority stress exposure may be associated with decreased activation and functional connectivity within the default-mode network (related to the sense-of-self and social cognition), and summarize preliminary evidence related to aberrant neural dynamics within the salience network (involved in threat detection and fear processing) and the central executive network (involved in executive functioning and emotion regulation). Importantly, this parallels neural adaptations commonly observed among individuals with posttraumatic stress disorder (PTSD) in the aftermath of trauma and supports the inclusion of insidious forms of trauma related to minority stress within models of PTSD. Conclusions: Taken together, minority stress may have several shared neuropsychological pathways with PTSD and stress-related disorders. Here, we outline a detailed research agenda that provides an overview of literature linking sexual minority stress to PTSD and insidious trauma, moral affect (including shame and guilt), and mental health risk/resiliency, in addition to racial, ethnic, and gender related minority stress. Finally, we propose a novel minority mosaic framework designed to inform future directions of minority stress neuroimaging research from an intersectional lens

IRX-2, a Novel Immunotherapeutic, Enhances Functions of Human Dendritic Cells

Background: In a recent phase II clinical trial for HNSCC patients, IRX-2, a cell-derived biologic, promoted T-cell infiltration into the tumor and prolonged overall survival. Mechanisms responsible for these IRX-2-mediated effects are unknown. We hypothesized that IRX-2 enhanced tumor antigen-(TA)-specific immunity by up-regulating functions of dendritic cells (DC). Methodology/Principal Findings: Monocyte-derived DC obtained from 18 HNSCC patients and 12 healthy donors were matured using IRX-2 or a mix of TNF-α, IL-1β and IL-6 ("conv. mix"). Multicolor flow cytometry was used to study the DC phenotype and antigen processing machinery (APM) component expression. ELISPOT and cytotoxicity assays were used to evaluate tumor-reactive cytotoxic T lymphocytes (CTL). IL-12p70 and IL-10 production by DC was measured by Luminex® and DC migration toward CCL21 was tested in transwell migration assays. IRX-2-matured DC functions were compared with those of conv. mix-matured DC. IRX-2-matured DC expressed higher levels (p<0.05) of CD11c, CD40, CCR7 as well as LMP2, TAP1, TAP2 and tapasin than conv. mix-matured DC. IRX-2-matured DC migrated significantly better towards CCL21, produced more IL-12p70 and had a higher IL12p70/IL-10 ratio than conv. mix-matured DC (p<0.05 for all). IRX-2-matured DC carried a higher density of tumor antigen-derived peptides, and CTL primed with these DC mediated higher cytotoxicity against tumor targets (p<0.05) compared to the conv. mix-matured DC. Conclusion: Excellent ability of IRX-2 to induce ex vivo DC maturation in HNSCC patients explains, in part, its clinical benefits and emphasizes its utility in ex vivo maturation of DC generated for therapy. © 2013 Schilling et al

DRD1 signaling modulates TrkB turnover and BDNF sensitivity in direct pathway striatal medium spiny neurons

Disturbed motor control is a hallmark of Parkinson's disease (PD). Cortico-striatal synapses play a central role in motor learning and adaption, and brain-derived neurotrophic factor (BDNF) from cortico-striatal afferents modulates their plasticity via TrkB in striatal medium spiny projection neurons (SPNs). We studied the role of dopamine in modulating the sensitivity of direct pathway SPNs (dSPNs) to BDNF in cultures of fluorescence-activated cell sorting (FACS)-enriched D1-expressing SPNs and 6-hydroxydopamine (6-OHDA)-treated rats. DRD1 activation causes enhanced TrkB translocation to the cell surface and increased sensitivity for BDNF. In contrast, dopamine depletion in cultured dSPN neurons, 6-OHDA-treated rats, and postmortem brain of patients with PD reduces BDNF responsiveness and causes formation of intracellular TrkB clusters. These clusters associate with sortilin related VPS10 domain containing receptor 2 (SORCS-2) in multivesicular-like structures, which apparently protects them from lysosomal degradation. Thus, impaired TrkB processing might contribute to disturbed motor function in PD.This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) project 424778381 (TRR295, A05, A06, and A01), project SE697/7-1, and project 218894895 (INST93/761-1FUGG). R.L.M.was supported by the Alexander von Humboldt-Stiftung. V.P. and C.S.were supported by GRK2581 (P6) SPHINGOINF of the DFG.Work in the lab of R.M. was supported by grant PID2019-111693RB-100 from MICIN/AEI/10.13039/501100011033, the European Union’s Horizon 2020 research and innovation program, AND-PD (grant 84800),Next Generation EU/PRTR (MICIN/CSIC/PTI+NeuroAging), and CIBERNED, Instituto de Salud Carlos III. The graphical abstract was created with BioRender.com. We thank Drs.James Surmeier, Moses Chao, and Esther Asan for critical comments and suggestions