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Context. Atmospheres above lava-ocean planets (LOPs) hold clues related to the properties of their interiors, based on the expectation that the two reservoirs are in chemical equilibrium. Furthermore, such atmospheres are observable with current-generation space- and ground-based telescopes. While efforts have been made to understand how emission spectra are related to the composition of the lava ocean, the influence of oxygen fugacity has yet to be examined in a self-consistent way. Aims. Here, we investigate the sensitivity of atmospheric emission spectra of LOPs to key geochemical parameters, namely, temperature (T), composition (X), and oxygen fugacity (fO2). We also consider the precision involved in recovering these spectra from observations of hot, rocky exoplanets. Methods. We considered 'mineral' atmospheres produced in equilibrium with silicate liquids. We treated fO2 as an independent variable, together with T and X, to compute equilibrium partial pressures (p) of stable gas species at the liquid-gas interface. Above this boundary, the atmospheric speciation and the pressure–temperature structure are computed self-consistently to yield emission spectra. We explored a wide array of plausible compositions, oxygen fugacities (between 6 log10 units below and above the iron-wüstite buffer, IW), and irradiation temperatures (2000, 2500, 3000, and 3500 K) relevant to LOPs. Results. We find that SiO(g), Fe(g) and Mg(g) are the major species below ~IW, ceding to O2(g) and O(g) in more oxidised atmospheres. The transition between the two regimes demarcates a minimum in total pressure (P). Because p scales linearly with X, emission spectra are only modest functions of composition. By contrast, fO2 can vary over orders of magnitude, thereby causing commensurate changes in p. Atmospheres outgassed from reducing melts exhibit intense SiO emission, creating a temperature inversion in the upper atmosphere. Conversely, oxidised atmospheres have lower pSiO and lack thermal inversions, with their resulting emission spectra mimicking that of a black-body. Consequently, the intensity of SiO emission relative to the background, generated by MgO(g), can be used to quantify the fO2 of the atmosphere. Depending on the emission spectroscopy metric of the target, deriving the fO2 of known nearby LOPs is possible with a few secondary occultations observed by JWST. [ABSTRACT FROM AUTHOR]

Compartmental models that describe infectious disease transmission across subpopulations are central for assessing the impact of non-pharmaceutical interventions, behavioral changes and seasonal effects on the spread of respiratory infections. We present a Bayesian workflow for such models, including four features: (1) an adjustment for incomplete case ascertainment, (2) an adequate sampling distribution of laboratory-confirmed cases, (3) a flexible, time-varying transmission rate, and (4) a stratification by age group. Within the workflow, we benchmarked the performance of various implementations of two of these features (2 and 3). For the second feature, we used SARS-CoV-2 data from the canton of Geneva (Switzerland) and found that a quasi-Poisson distribution is the most suitable sampling distribution for describing the overdispersion in the observed laboratory-confirmed cases. For the third feature, we implemented three methods: Brownian motion, B-splines, and approximate Gaussian processes (aGP). We compared their performance in terms of the number of effective samples per second, and the error and sharpness in estimating the time-varying transmission rate over a selection of ordinary differential equation solvers and tuning parameters, using simulated seroprevalence and laboratory-confirmed case data. Even though all methods could recover the time-varying dynamics in the transmission rate accurately, we found that B-splines perform up to four and ten times faster than Brownian motion and aGPs, respectively. We validated the B-spline model with simulated age-stratified data. We applied this model to 2020 laboratory-confirmed SARS-CoV-2 cases and two seroprevalence studies from the canton of Geneva. This resulted in detailed estimates of the transmission rate over time and the case ascertainment. Our results illustrate the potential of the presented workflow including stratified transmission to estimate age-specific epidemiological parameters. The workflow is freely available in the R package HETTMO, and can be easily adapted and applied to other infectious diseases. Author summary: Mathematical models are a central tool for understanding the spread of infectious diseases. These models can frequently be fitted to surveillance data such as the number of laboratory-confirmed cases and seroprevalence over time. We identified that in these situations, four crucial features are required for a model to provide insightful information for managing an epidemic. These features relate to the adjustment for incomplete case ascertainment, to the choice of sampling distribution, to the variation of transmission over time and to the stratification by age. For each feature, we identify and compare several implementation options on simulated data. This structural comparison of methods results in a Bayesian workflow that is optimized for modeling the transmission of SARS-CoV-2 over a short period. We highlight the advantages and limitations of our approach in a real situation, using real-world SARS-CoV-2 data from the canton of Geneva. In addition to providing validated solutions to important technical points, such a comprehensive workflow helps to improve the reliability and the transparency of epidemic models. [ABSTRACT FROM AUTHOR]

The present essay deals with the centres of the growing and dynamic Zurich agglomeration, notably those in the communities of Schlieren, Thalwil, and Wallisellen. The primary study focus of this City Tour is the area around the train stations in the centres presented. The theoretical foundation touches on approaches of the relational theory of space, the conceptualisation of a Swiss-specific Zwischenstadt (Thomas Sieverts) and non-lieux (Marc Augé). As a result of industrialisation and urbanisation processes, the central district in these three communities has moved away from the historic town centres. With the construction of train stations outside the former community boundaries, a new place of centrality has developed. Today, a second shift in these central areas can be witnessed. Current transformation processes result in the 'rear side' of the train station now being developed as an extended central area. Although these real estate developments should result in upgrades of public spaces, the urban pathways crossing the railway infrastructures are often poorly developed. In reality, these underpasses and passages are purely functional non-spaces. The conclusion of this essay frames an answer on possible planning approaches for how this urban development and socio-spatial deficit might be solved. English title: The centres of the Zurich agglomeration and the transformation of the 'rear sides' [ABSTRACT FROM AUTHOR]

General circulation models (GCMs) provide context for interpreting multiwavelength, multiphase data of the atmospheres of tidally locked exoplanets. In the current study, the non-hydrostatic THOR GCM is coupled with the HELIOS radiative transfer solver for the first time, supported by an equilibrium chemistry solver (FastChem), opacity calculator (HELIOS-K), and Mie scattering code (LX-MIE). To accurately treat the scattering of radiation by medium-sized to large aerosols/condensates, improved two-stream radiative transfer is implemented within a GCM for the first time. Multiple scattering is implemented using a Thomas algorithm formulation of the two-stream flux solutions, which decreases the computational time by about 2 orders of magnitude compared to the iterative method used in past versions of HELIOS. As a case study, we present four GCMs of the hot Jupiter WASP-43b, where we compare the temperature, velocity, entropy, and streamfunction, as well as the synthetic spectra and phase curves, of runs using regular versus improved two-stream radiative transfer and isothermal versus non-isothermal layers. While the global climate is qualitatively robust, the synthetic spectra and phase curves are sensitive to these details. A THOR + HELIOS WASP-43b GCM (horizontal resolution of about 4 deg on the sphere and with 40 radial points) with multiwavelength radiative transfer (30 k-table bins) running for 3000 Earth days (864 000 time-steps) takes about 19–26 d to complete depending on the type of GPU. [ABSTRACT FROM AUTHOR]

Accurate line lists are crucial for correctly modelling a variety of astrophysical phenomena, including stellar photospheres and the atmospheres of extrasolar planets. This paper presents a new line database Toto for the main isotopologues of titanium oxide (TiO): |$^{46}\text{Ti}^{16}\text{O}$|⁠ , |$^{47}\text{Ti}^{16}\text{O}$|⁠ , |$^{48}\text{Ti}^{16}\text{O}$|⁠ , |$^{49}\text{Ti}^{16}\text{O}$|⁠ , and |$^{50}\text{Ti}^{16}\text{O}$|⁠. The |$^{48}\text{Ti}^{16}\text{O}$| line list contains transitions with wave-numbers up to 30 000 cm−1, i.e. longwards of 0.33 μm. The Toto line list includes all dipole-allowed transitions between 13 low-lying electronic states (X 3Δ, a1Δ, d 1Σ+, E 3Π, A 3Φ, B3Π, C 3Δ, b 1Π, c1Φ, f1Δ, e 1Σ+). Ab initio potential energy curves (PECs) are computed at the icMRCI level and combined with spin–orbit and other coupling curves. These PECs and couplings are iteratively refined to match known empirical energy levels. Accurate line intensities are generated using ab initio dipole moment curves. The Toto line lists are appropriate for temperatures below 5000 K and contain 30 million transitions for |$^{48}\text{Ti}^{16}\text{O}$|⁠ ; it is made available in electronic form via the CDS data centre and via www.exomol.com. Tests of the line lists show greatly improved agreement with observed spectra for objects such as M-dwarfs GJ876 and GL581. [ABSTRACT FROM AUTHOR]

Current observational data of exoplanets are providing increasing detail of their 3D atmospheric structures. As characterization efforts expand in scope, the need to develop consistent 3D radiative-transfer methods becomes more pertinent as the complex atmospheric properties of exoplanets are required to be modelled together consistently. We aim to compare the transmission and emission spectra results of a 3D Monte Carlo radiative transfer (MCRT) model to contemporary radiative-transfer suites. We perform several benchmarking tests of an MCRT code, Cloudy Monte Carlo Radiative Transfer (cmcrt), to transmission and emission spectra model output. We add flexibility to the model through the use of k -distribution tables as input opacities. We present a hybrid MCRT and ray tracing methodology for the calculation of transmission spectra with a multiple scattering component. cmcrt compares well to the transmission spectra benchmarks at the 10s of ppm level. Emission spectra benchmarks are consistent to within 10 per cent of the 1D models. We suggest that differences in the benchmark results are likely caused by geometric effects between plane-parallel and spherical models. In a practical application, we post-process a cloudy 3D HD 189733b GCM model and compare to available observational data. Our results suggest the core methodology and algorithms of cmcrt produce consistent results to contemporary radiative transfer suites. 3D MCRT methods are highly suitable for detailed post-processing of cloudy and non-cloudy 1D and 3D exoplanet atmosphere simulations in instances where atmospheric inhomogeneities, significant limb effects/geometry or multiple scattering components are important considerations. [ABSTRACT FROM AUTHOR]

Context. The TRAPPIST-1 system hosts seven Earth-sized, temperate exoplanets orbiting an ultra-cool dwarf star. As such, it represents a remarkable setting to study the formation and evolution of terrestrial planets that formed in the same protoplanetary disk. While the sizes of the TRAPPIST-1 planets are all known to better than 5% precision, their densities have significant uncertainties (between 28% and 95%) because of poor constraints on the planet's masses. Aims. The goal of this paper is to improve our knowledge of the TRAPPIST-1 planetary masses and densities using transit-timing variations (TTVs). The complexity of the TTV inversion problem is known to be particularly acute in multi-planetary systems (convergence issues, degeneracies and size of the parameter space), especially for resonant chain systems such as TRAPPIST-1. Methods. To overcome these challenges, we have used a novel method that employs a genetic algorithm coupled to a full N-body integrator that we applied to a set of 284 individual transit timings. This approach enables us to efficiently explore the parameter space and to derive reliable masses and densities from TTVs for all seven planets. Results. Our new masses result in a five- to eight-fold improvement on the planetary density uncertainties, with precisions ranging from 5% to 12%. These updated values provide new insights into the bulk structure of the TRAPPIST-1 planets. We find that TRAPPIST-1 c and e likely have largely rocky interiors, while planets b, d, f, g, and h require envelopes of volatiles in the form of thick atmospheres, oceans, or ice, in most cases with water mass fractions less than 5%. [ABSTRACT FROM AUTHOR]

Terrestrial planets are thought to be the result of a vast number of gravitational interactions and collisions between smaller bodies. We use numerical simulations to show that practically identical initial conditions result in a wide array of final planetary configurations. This is a result of the chaotic evolution of trajectories which are highly sensitive to minuscule displacements. We determine that differences between systems evolved from virtually identical initial conditions can be larger than the differences between systems evolved from very different initial conditions. This implies that individual simulations lack predictive power. For example, there is not a reproducible mapping between the initial and final surface density profiles. However, some key global properties can still be extracted if the statistical spread across many simulations is considered. Based on these spreads, we explore the collisional growth and orbital properties of terrestrial planets, which assemble from different initial conditions (we vary the initial planetesimal distribution, planetesimal masses, and giant planet orbits.). Confirming past work, we find that the resulting planetary systems are sculpted by sweeping secular resonances. Configurations with giant planets on eccentric orbits produce fewer and more massive terrestrial planets on tighter orbits than those with giants on circular orbits. This is further enhanced if the initial mass distribution is biased to the inner regions. In all cases, the outer edge of the system is set by the final location of the ν6 resonance and we find that the mass distribution peaks at the ν5 resonance. Using existing observations, we find that extrasolar systems follow similar trends. Although differences between our numerical modelling and exoplanetary systems remain, we suggest that CoRoT-7, HD 20003 and HD 20781 may host undetected giant planets. [ABSTRACT FROM AUTHOR]

Cultured mammalian cells exhibit elevated glycolysis flux and high lactate production. In the industrial bioprocesses for biotherapeutic protein production, glucose is supplemented to the culture medium to sustain continued cell growth resulting in the accumulation of lactate to high levels. In such fed-batch cultures, sometimes a metabolic shift from a state of high glycolysis flux and high lactate production to a state of low glycolysis flux and low lactate production or even lactate consumption is observed. While in other cases with very similar culture conditions, the same cell line and medium, cells continue to produce lactate. A metabolic shift to lactate consumption has been correlated to the productivity of the process. Cultures that exhibited the metabolic shift to lactate consumption had higher titers than those which didn’t. However, the cues that trigger the metabolic shift to lactate consumption state (or low lactate production state) are yet to be identified. Metabolic control of cells is tightly linked to growth control through signaling pathways such as the AKT pathway. We have previously shown that the glycolysis of proliferating cells can exhibit bistability with well-segregated high flux and low flux states. Low lactate production (or lactate consumption) is possible only at a low glycolysis flux state. In this study, we use mathematical modeling to demonstrate that lactate inhibition together with AKT regulation on glycolysis enzymes can profoundly influence the bistable behavior, resulting in a complex steady-state topology. The transition from the high flux state to the low flux state can only occur in certain regions of the steady state topology, and therefore the metabolic fate of the cells depends on their metabolic trajectory encountering the region that allows such a metabolic state switch. Insights from such switch behavior present us with new means to control the metabolism of mammalian cells in fed-batch cultures. [ABSTRACT FROM AUTHOR]

Exchange of the native Corynebacterium glutamicum promoter of the aceE gene, encoding the Elp subunit of the pyruvate dehydrogenase complex (PDHC), with mutated dapA promoter variants led to a series of C. glutamicum strains with gradually reduced growth rates and PDHC activities. Upon overexpression of the l-valine biosynthetic genes UvBNCE, all strains produced l-valine. Among these strains, C. glutamicum aceE A16 (pJC4 livBNCE) showed the highest biomass and product yields, and thus it was further improved by additional deletion of the pqo and ppc genes, encoding pyruvate:quinone oxidoreductase and phosphoenolpyruvate carboxylase, respectively. In fed-batch fermentations at high cell densities, C. glutamicum aceE A16 Δpqo Δppc (pJC4 livBNCE) produced up to 738 mM (i.e., 86.5 g/liter) L-valine with an overall yield (YP/S) of 0.36 mol per mol of glucose and a volumetric productivity (QP) of 13.6 mM per h [1.6 g/(liter x h)]. Additional inactivation of the transaminase B gene (ilvE) and overexpression of ilvBNCD instead of UvBNCE transformed the L-valine-producing strain into a 2-ketoisovalerate producer, excreting up to 303 mM (35 g/liter) 2-ketoisovalerate with a Yp/s of 0.24 mol per mol of glucose and a Qp of 6.9 mM per h [0.8 g/(liter X h)]. The replacement of the aceE promoter by the dapA-A16 promoter in the two C. glutamicum L-lysine producers DM1800 and DM1933 improved the production by 100% and 44%, respectively. These results demonstrate that C. glutamicum strains with reduced PDHC activity are an excellent platform for the production of pyruvate-derived products. [ABSTRACT FROM AUTHOR]