We report the early discovery and multicolor (BVI) high-cadence light-curve analyses of the rapidly declining sub-Chandrasekhar Type Ia supernova KSP-OT-201509b (= AT 2015cx) from the KMTNet Supernova Program. The Phillips and color stretch parameters of KSP-OT-201509b are Delta M-B,M-15 1.62 mag and s(BV) 0.54, respectively, at an inferred redshift of 0.072. These, together with other measured parameters (such as the strength of the secondary I-band peak, colors, and luminosity), identify the source to be a rapidly declining Type Ia of a transitional nature that is closer to Branch-normal than 91bg-like. Its early light-curve evolution and bolometric luminosity are consistent with those of homologously expanding ejecta powered by radioactive decay and a Type Ia SN explosion with 0.32 0.01 M of synthesized Ni-56 mass, 0.84 0.12 M of ejecta mass, and (0.61 0.14) x 10(51) erg of ejecta kinetic energy. While its B - V and V - I colors evolve largely synchronously with the changes in the I-band light curve, as found in other supernovae, we also find the presence of an early redward evolution in V - I prior to -10 days since peak. The bolometric light curve of the source is compatible with a stratified Ni-56 distribution extended to shallow layers of the exploding progenitor. Comparisons between the observed light curves and those predicted from ejecta-companion interactions clearly disfavor Roche lobe-filling companion stars at large separation distances, thus supporting a double-degenerate scenario for its origin. The lack of any apparent host galaxy in our deep stack images reaching a sensitivity limit of similar to 28 mag arcsec(-2) makes KSP-OT-201509b a hostless Type Ia supernova and offers new insights into supernova host galaxy environments.

There has been considerable recent interest in the high-pressure behavior of silicon carbide, a potential major constituent of carbon-rich exoplanets. In this work, the atomic-level structure of SiC was determined through in situ X-ray diffraction under laser-driven ramp compression up to 1.5 TPa; stresses more than seven times greater than previous static and shock data. Here we show that the B1-type structure persists over this stress range and we have constrained its equation of state (EOS). Using this data we have determined the first experimentally based mass-radius curves for a hypothetical pure SiC planet. Interior structure models are constructed for planets consisting of a SiC-rich mantle and iron-rich core. Carbide planets are found to be similar to 10% less dense than corresponding terrestrial planets.

The Earth's fluid budget is dominated by species in the system C-O-H-N-S together with halogens such as F and Cl. H2O is by far the most abundant. Such fluids are one of the two main mass transport agents (fluid and magma) in the Earth. Among those, in particular aqueous fluids are efficient solvents of geochemically important components at high temperature and pressure. The solution capacity of aqueous fluids can be enhanced further by dissolved halogens and sulfur. CO2 or nitrogen species has the opposite effect.

The complexity of microbial communities suggests prevalent interactions involving more than just pairs of species. These so-called higher-order interactions may reveal new molecules that enable bacteria to deal with complex environments. This forum article discusses how higher-order interactions can be detected and why molecular biologists might care.

An outstanding goal in planetary science is to understand how terrestrial cores evolved to have the compositions, thermal properties, and magnetic fields observed today. To achieve that aim requires the integration of datasets from space missions with laboratory experiments conducted at high pressures and temperatures. Over the past decade, technological advances have enhanced the capability to conduct in situ measurements of physical properties on samples that are analogs to planetary cores. These challenging experiments utilize large-volume presses that optimize control of pressure and temperature, and diamond-anvil cells to reach the highest pressures. In particular, the current experimental datasets of density, compressional velocity, viscosity, and thermal conductivity of iron alloys are most relevant to the core conditions of small terrestrial planets and moons. Here we review the physical properties of iron alloys measured in the laboratory at conditions relevant to the cores of Mars, the Moon, and Mercury. We discuss how these properties inform models of core composition, as well as thermal and magnetic evolution of their cores. Experimental geochemistry (in particular, metal-silicate partitioning experiments) provides additional insights into the nature and abundance of light elements within cores, as well as crystallization processes. Emphasis is placed on the Martian core to discuss the effect of chemistry on core evolution.

Cells respond to physicalstimuli, such as stiffness1, fluid shear stress2 and hydraulic pressure3,4. Extracellular fluid viscosity is a key physical cue that varies under physiological and pathological conditions, such as cancer5. However, its influence on cancer biology and the mechanism by which cells sense and respond to changes in viscosity are unknown. Here we demonstrate that elevated viscosity counterintuitively increases the motility of various cell types on two-dimensional surfaces and in confinement, and increases cell dissemination from three-dimensional tumour spheroids. Increased mechanical loading imposed by elevated viscosity induces an actin-related protein 2/3 (ARP2/3)-complex-dependent dense actin network, which enhances Na+/H+ exchanger 1 (NHE1) polarization through its actin-binding partner ezrin. NHE1 promotes cell swelling and increased membrane tension, which, in turn, activates transient receptor potential cation vanilloid 4 (TRPV4) and mediates calcium influx, leading to increased RHOA-dependent cell contractility. The coordinated action of actin remodelling/dynamics, NHE1-mediated swelling and RHOA-based contractility facilitates enhanced motility at elevated viscosities. Breast cancer cells pre-exposed to elevated viscosity acquire TRPV4-dependent mechanical memory through transcriptional control of the Hippo pathway, leading to increased migration in zebrafish, extravasation in chick embryos and lung colonization in mice. Cumulatively, extracellular viscosity is a physical cue that regulates both short- and long-term cellular processes with pathophysiological relevance to cancer biology.

The Local Volume Mapper (LVM) project among the fifth iteration of the Sloan Digital Sky Survey (SDSS-V) plans to produce large integral-field spectroscopic survey data. The data will reveal the physical conditions of the interstellar medium in the Milky Way, the Magellanic Clouds, and other local-volume galaxies. We developed the Local Volume Mapper Spectrograph Control Package (LVMSCP) which controls the spectrograph subsystem. The architecture design of the software based on Python 3.9 follows a hierarchical structure composed of high-level, mid-level, low-level software packages, and hardware components. We used the new SDSS message passing protocol CLU for the interaction, based on RabbitMQ that implemented the Advanced Message Queuing Protocol (AMQP). The Actors that receive or produce messages to each other are also the units of the conceptual operation. Furthermore, the package applies asynchronous programming with non-blocking procedures since the three spectrographs should operate simultaneously. For requirement of the incremental code change and management in the collaboration of the developers, we adopted the SDSS Github Action which supports Continuous Integration (CI) / Continuous Deployment (CD). As a part of this, Unit testing with Pytest tests the individual components of a software respectively. Finally, the LVMSCP provides the Application Programming Interface (API) to the Robotic Observation Package (ROP) for the integrated observation to fulfill the required scientific survey execution for the spectrographs.

Sloan Digital Sky Survey fifth-generation (SDSS-V) Local Volume Mapper (LVM) is a wide-field IFU survey that uses an array of four 160 mm telescopes. It provides IFU spectra over the optical range with R similar to 4,000 to reveal the inner components of galaxies and the evolution of the universe. Each telescope observes the science field or the calibration field independently, but all of them should be simultaneously synchronized with the science exposure. To minimize the moving parts, the LVM adopted the siderostat design with a field derotator. We designed the optimized control software for our LVM observation, lvmagp, which controls four focusers, three K-mirror derotators, one fiber selector, four mounts (siderostats), and seven guide cameras. It was built on its owen user interface and messaging protocol called actor and clu based on asynchronous programming. The lvmagp provides three key sequences: autofocus sequence, field acquisition sequence, and autoguide sequence. Also, we designed and fabricated the proto-model siderostat for the software test. The real sky test was made with proto-model siderostat, and the lvmagp showed arcsecond-level field acquisition and autoguide accuracy.

The Sloan Digital Sky Survey V (SDSS-V) is an all-sky, multi-epoch spectroscopic survey designed to decode the stellar evolution of the Milky Way, reveal the inner workings of stars, study the interstellar medium in the Local Volume of galaxies, and track the growth of supermassive black holes across the Universe. SDSS-V presents significant innovations in hardware and instrumentation, with the introduction of a new Focal Plane System instrument that enables multi-object spectroscopy using an array of 500 robotic fibre positioners, and the development of a new robotic observatory for the Local Volume Mapper program. These advances in instrumentation and operations necessitate a similarly evolved computing and software architecture to ensure survey efficiency and to take advantage of the improvements in software engineering and development. In this paper we present the cyberinfrastructure of the SDSS project with focus on the changes introduced since the previous iteration of the project, the adoption of new technologies, and the lessons learned in this process.

The thermal conductivities of mantle and core materials have a major impact on planetary evolution, but their experimental determination requires precise knowledge of sample thickness at high pressure. Despite its importance, thickness in most diamond anvil cell (DAC) experiments is not measured but inferred from equations of state, assuming isotropic contraction upon compression or assuming isotropic expansion upon decompression. Here we provide evidence that in DAC experiments both assumptions are invalid for a range of mechanically diverse materials (KCl, NaCl, Ar, MgO, silica glass, Al2O3). Upon compression, these samples are similar to 30-50% thinner than expected from isotropic contraction. Most surprisingly, all the studied samples continue to thin upon decompression to 10-20 GPa. Our results partially explain some discrepancies among the highly controversial thermal conductivity values of iron at Earth's core conditions. More generally, we suggest that in situ characterization of sample geometry is essential for conductivity measurements at high pressure.