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In order to improve our understanding of the interior structure of Saturn's small moon Enceladus, we reanalyze radiometric tracking and onboard imaging data acquired by the Cassini spacecraft during close encounters with the moon. We compute the global shape, gravity field, and rotational parameters of Enceladus in a reference frame consistent with the International Astronomical Union's definition, where the center of the Salih crater is located at −5° East longitude. We recover a quadrupole gravity field with J3 and a forced libration amplitude of 0.091° ± 0.009° (3‐σ). We also compute a global shape model using a stereo‐photoclinometry technique with a global resolution of 500 m, although some local maps have higher resolutions ranging from 25 to 100 m. While our overall results are generally consistent with previous studies, we infer a thicker 27–33 km mean ice shell, a thinner 21–26 km mean ocean thickness, and a mean core density range of 2,270–2,330 kg/m3. Plain Language Summary: Geodetic data, such as shape, gravity, and rotation, provide important constraints for probing a planetary body's interior structure. We analyze radiometric tracking and onboard imaging data acquired during close encounters of Enceladus by the Cassini spacecraft to compute geodetic products including topographic and gravitational fields in a common reference frame. The recovered Enceladus topography has a global resolution of 500 m, with some local regions having 25–100 m resolution. Our study suggests that Enceladus has a 27–33 km mean ice shell thickness, a 21–26 km mean ocean thickness, and a mean core density range of 2,270–2,330 kg/m3. Key Points: A full quadrupole gravity field with J3 and the forced libration amplitude of 0.091° ± 0.009° are recoveredA 500‐m resolution global topography model was computed, with some local regions having 25−100 m resolutionThe results suggest that Enceladus has a 27–33 km mean ice shell thickness, a 21–26 km ocean thickness, and a mean core density range of 2,270–2,330 kg/m3 [ABSTRACT FROM AUTHOR]

The open‐source PlanetProfile framework was developed to investigate the interior structure of icy moons based on collectively matching their observed properties and comparative planetology. The software relates observed and measured properties, assumptions such as the type of materials present, and laboratory equation‐of‐state (EOS) data through geophysical and thermodynamic models to evaluate radial profiles of mechanical, thermodynamic, and electrical properties, as self‐consistently as possible. We have created a Python version of PlanetProfile. In the process, we have made optimization improvements and added parallelization and parameter‐space search features to utilize fast operation for investigating unresolved questions in planetary geophysics, in which many model inputs are poorly constrained. The Python version links to other scientific software packages, including for evaluating EOS data, magnetic induction calculations, and seismic calculations. Physical models in PlanetProfile have been reconfigured to improve self‐consistency and generate the most realistic relationships between properties. In this work, we focus on the description of the software design and algorithms in detail, summarize model results for major moons across the outer solar system, and discuss new inferences about the interior structure of several bodies. The high values and narrow uncertainty ranges reported for the axial moments of inertia for Callisto, Titan, and Io are difficult to reconcile with the realistic physical and chemical approximations applied, requiring highly porous rock layers equivalent to incomplete differentiation for Callisto and Titan, and a high rock melt fraction for Io. Radial profiles for each model and comparison to prior work are provided as Zenodo archives. Plain Language Summary: The software package PlanetProfile was developed in order to connect measurable properties of planetary bodies to each other and determine how planetary interiors might be structured. We adapted the existing Matlab version of PlanetProfile to Python and improved it in many ways in the process, to better investigate scientific questions. Python is more widely available, and PlanetProfile now connects better to other scientific software packages capable of relating measurements and observations to the interior structure of planetary bodies such as large moons. PlanetProfile is now more adaptable for new scientific investigations and adding features, includes more realistic relationships between pressures, temperatures, and physical properties of materials, and is optimized for studies that require a wide variety of models to be run. These improvements make PlanetProfile a powerful tool that will become more useful as new features are added. We summarize our models for the major large moons in the outer solar system and provide output files detailing each model. In creating these models, we found that bulk properties for Io, Callisto, and Titan are difficult to combine together into realistic models, which suggests that the reported values may contain errors. Key Points: Radial models of planetary interiors are generated from bulk properties based on geophysical models, lab data, and minimal assumptionsBodies with a high moment of inertia such as Callisto require low‐density rocks, which we model with a high effective porosityModels are optimized for wide parameter‐space searches as needed for investigating unresolved questions about planetary interiors [ABSTRACT FROM AUTHOR]

As this and previous editions of "New Directions for Community Colleges" have argued, digital skills are necessary. Our future economy will be based on them, but there is no consensus on which skills to teach. Many talk about Web 2.0 skills, familiarity with software, and critical thinking skills, yet few mention the potential of video games in education. This chapter examines the potential for using video games at the community college level, possible arguments against it, and necessary support from administration, information technology departments, and libraries to make the most of this digital technology.

There have been many attempts to understand how the Internet affects our modern world. There have also been numerous attempts to understand specific areas of the Internet. This article applies Immanuel Wallerstein's World Systems Analysis to our informationalist society. Understanding this world as divided among individual core, semi-periphery, and periphery members adds greater clarity to studies of subsections of the world, digital and otherwise.

Modeling of the electrical conductivity (EC) of icy moon oceans has previously assumed that chloride, sulfate, and other ions released from rock leaching are the main solutes and carriers of EC. Here, we show that accreted volatiles, such as carbon dioxide and ammonia, can add a significant fraction of solutes in bodies whose volatile content was in part supplied from cometary materials. These volatiles can increase the EC of aqueous solutions above 1 S/m. Our salinity and EC estimates can serve as a basis for planning future magnetometer investigations at icy moons and dwarf planets. In particular, oceans expected in some of the Uranian satellites and Neptune's satellite Triton could have EC above 3 S/m as a result of accretion of both carbon dioxide and ammonia, even if rock leaching during water‐rock separation was limited, and if chlorine and sulfur abundances may be at CI carbonaceous chondritic levels. Plain Language Summary: Searching for deep oceans in icy bodies is a major driver of planetary exploration. Magnetometry is used to detect electric currents in deep oceans generated by a varying magnetic field, from a giant planet or solar wind, as was done at Jupiter's moon Europa during the Galileo mission. Previous studies have assumed that the salinity of deep oceans is determined by the leaching of major elements from accreted rock, which may yield brackish and low electrical conductivity solutions. We show that carbon dioxide, an abundant ice in the outer solar system, could contribute a significant fraction of solutes (carbonate and bicarbonate ions) in ocean worlds, regulated in particular by the presence of ammonia. The latest solar system dynamical models predict that dwarf planets and most icy moons accreted ices rich in carbon dioxide and ammonia. If oceans exist today inside these bodies, the resulting ion concentrations would produce a stronger magnetic signature than previously expected, perhaps detectable by future spacecraft missions. Key Points: Accreted CO2 and NH3 ices can significantly increase the salinity and electrical conductivity (EC) of deep oceansWater to rock ratio and ammonia abundance drive the concentrations of carbonate and bicarbonate ions in solutionPredicted EC estimates can be used to plan future ocean search missions at icy moons and dwarf planets [ABSTRACT FROM AUTHOR]

Detecting a seismic event from Europa's silicate interior would provide information about the geologic and tectonic setting of the moon's rocky interior. However, the subsurface ocean will attenuate the signal, possibly preventing the waveforms from being detected by a surface seismometer. Here, we investigate the minimum magnitude of a detectable event originating from Europa's silicate interior. We analyze likely signal‐to‐noise ratios and compare the predicted signal strengths to current instrument sensitivities. We show that a magnitude Mw ≥ 3.5 would be sufficient to overcome the predicted background noise when the ice shell is 5 km thick. However, a minimum magnitude of Mw ≥ 5.5 would be required for current instrumentation to be able detect the event for any ice shell thickness, at any distance. A thinner ice shell transmits greater ground acceleration amplitudes than a thicker ice shell, which might allow for Mw ≥ 4.5 to be detectable. Plain Language Summary: Europa, one of Jupiter's moons, has an icy surface overlying a subsurface ocean and rocky interior. Europa's surface is likely geologically active and its rocky interior may also produce seismic events. Here, we investigate if data from a seismometer could detect and record signals originating from the rocky interior, thus allowing a science team to accurately determine if the interior is also geologically active. We compare the resulting ground motion from a deep event to predicted background noise and instrument capabilities. We find that an event with a magnitude of at least a 3.5 would overcome background noise. However, current instrumentation would require an event of at least a magnitude 5.5 to be detectable from anywhere on Europa's surface. If such an event were to occur, we could use the recorded signal from a seismometer on Europa's surface to constrain the near‐surface and deep interior structure, and also to study the geologic setting and activity of the rocky interior. Key Points: Seismic events from Europa's silicate interior could reveal interior composition and structureThe subsurface ocean will likely dampen events and filter out shear wavesA euroquake will likely need to be over a Mw 5.0 to be detectable by current seismic instrumentation [ABSTRACT FROM AUTHOR]

Many moons in the solar system are thought to potentially harbor hidden oceans based on the features observed at their surfaces. However, the magnetic induction signatures measured in the vicinity of these moons provide the most compelling evidence for the presence of a subsurface ocean, specifically for the Jovian moons Europa and Callisto. Interpretation of these magnetic signatures can be challenging due to the various systematic and random sources of noise that are present in the magnetic field measurement. In this work, a novel magnetometric ocean detection methodology based on Principal Component Analysis is presented and shown to provide enhanced discrimination and geophysical characterization of ocean properties in the presence of noise and error sources. The proposed methodology is robust for a single‐encounter mission or an orbiting mission with multiple flybys. Here, it is applied to the Neptunian moon Triton as a prime example of an active, potential ocean world residing in the requisite time‐varying magnetic field environment that enables magnetic induction investigation of its interior. In addition to the usual noise sources, other confounding factors are addressed, including the presence of an intense conductive ionosphere, the small amplitude of Neptune's driving magnetic field, and the uncertainty of Neptune's magnetic phase at the time‐of‐arrival which can potentially hinder accurate ocean detection and characterization. The proposed methodology is applicable to any moon in the solar system residing in a time‐varying magnetic field environment. Plain Language Summary: The search for habitable oceans in the solar system motivates the need for advances in analytic techniques to positively determine the presence of subsurface oceans in challenging environments. The Principal Component Analysis (PCA) method described in this article is a new paradigm for processing space‐based magnetic field measurements for definitive detection and constrained characterization of subsurface oceans. Using Neptune's largest moon Triton as an example ocean world, PCA is directly applied to a three‐axis magnetic field data set and shown to be a powerful ocean classification tool for a single or multiple flybys, even in the presence of Triton's highly conducting ionosphere which can mask the magnetic response from the ocean. The method is able to reliably distinguish between the magnetic field signatures associated with the ocean‐plus‐ionosphere and ionosphere‐only model classes and can further determine key characteristics of the hidden ocean in the face of the confounding factors of a conductive ionosphere, local plasma current perturbations, spacecraft timing and position uncertainties, data outages, and various sources of instrument noise. The flexibility and extensibility afforded by the PCA‐based method enhance the existing and future capabilities for ocean detection and characterization at candidate ocean worlds throughout the solar system. Key Points: A novel sub‐surface ocean detection and characterization method has been developed based on Principal Component Analysis processing of magnetic induction dataEnables differentiation between ocean‐plus‐ionosphere and ionosphere‐only induction responses in the presence of various noise sourcesApplied here to the compelling target of Triton, thought to possibly harbor a sub‐surface ocean beneath a highly conducting ionosphere [ABSTRACT FROM AUTHOR]

The Galileo mission to Jupiter discovered magnetic signatures associated with hidden subsurface oceans at the moons Europa and Callisto using the phenomenon of magnetic induction. These induced magnetic fields originate from electrically conductive layers within the moons and are driven by Jupiter's strong time‐varying magnetic field. The ice giants and their moons are also ideal laboratories for magnetic induction studies. Both Uranus and Neptune have a strongly tilted magnetic axis with respect to their spin axis, creating a dynamic and strongly variable magnetic field environment at the orbits of their major moons. Although Voyager 2 visited the ice giants in the 1980s, it did not pass close enough to any of the moons to detect magnetic induction signatures. However, Voyager 2 revealed that some of these moons exhibit surface features that hint at recent geologically activity, possibly associated with subsurface oceans. Future missions to the ice giants may therefore be capable of discovering subsurface oceans, thereby adding to the family of known "ocean worlds" in our Solar System. Here, we assess magnetic induction as a technique for investigating subsurface oceans within the major moons of Uranus. Furthermore, we establish the ability to distinguish induction responses created by different interior characteristics that tie into the induction response: ocean thickness, conductivity and depth, and ionospheric conductance. The results reported here demonstrate the possibility of single‐pass ocean detection and constrained characterization within the moons of Miranda, Ariel, and Umbriel, and provide guidance for magnetometer selection and trajectory design for future missions to Uranus. Plain Language Summary: The best evidence for the existence of an ocean within Jupiter's moons of Europa and Callisto comes from interpretations of measurements collected from the magnetometer on the Galileo spacecraft. Their salty oceans are able to conduct electrical currents that are driven by Jupiter's strong time‐varying magnetic field, producing a unique secondary magnetic field signature that can be measured externally by as spacecraft passing by. Some of the large moons of the Ice Giant planets of Uranus and Neptune are also thought to possibly contain subsurface oceans. Unfortunately, Voyager 2 did not pass close enough to any of these planetary bodies for its onboard magnetometer to sense magnetic field signatures associated with a subsurface ocean. In this work, we investigate the feasibility of detecting magnetic signatures of subsurface oceans within the moons of Uranus based upon various assumed interior structure profiles, thus providing guidance to required magnetometer performance and trajectory design for possible future missions. Key Points: The major moons of Uranus exhibit surface features which hint at recent geologically activity, possibly associated with subsurface oceansFavorable geometry of the Uranus system facilitates magnetic induction investigation of potential oceans within the primary moonsSubsurface ocean detection and constrained characterization is possible within these moons, even in the presence of an ionosphere [ABSTRACT FROM AUTHOR]

Arabic has been held up as a model of diglossia with Modern Standard Arabic (MSA) representing the “high” variety and local dialects the “low” variety. Yet, Arabic is not merely two language varieties, and Arabic speakers do not merely switch between the two. Arabic speakers, instead, draw on an array of linguistic features along a heteroglossic continuum between MSA and vernacular varieties (including sociolects). Features are deployed in daily interactions triggered by formality, education, gender, stancetaking, and other variables. Understanding how to successfully deploy these features – translanguaging – is part of Arabic speakers’ communicative competence. Translanguaging, however, poses a challenge for learners of Arabic as an additional language. In response, greater emphasis on sociolinguistic competence is advocated to develop learners’ proficiency to more effectively function in Arabic-speaking communities. We suggest enhancing metalinguistic awareness early on through pragmatic-focused task-based activities scaffolded by explicit instruction about the forms and functions of Arabic features.

Summary: Increasing evidence suggests that free haem and iron exert vasculo‐toxic and pro‐inflammatory effects by activating endothelial and immune cells. In the present retrospective study, we compared serum samples from transfusion‐dependent patients with β‐thalassaemia major and intermedia, hereditary spherocytosis and sickle cell disease (SCD). Haemolysis, transfusions and ineffective erythropoiesis contribute to haem and iron overload in haemolytic patients. In all cohorts we observed increased systemic haem and iron levels associated with scavenger depletion and toxic 'free' species formation. Endothelial dysfunction, oxidative stress and inflammation markers were significantly increased compared to healthy donors. In multivariable logistic regression analysis, oxidative stress markers remained significantly associated with both haem‐ and iron‐related parameters, while soluble vascular cell adhesion molecule 1 (sVCAM‐1), soluble endothelial selectin (sE‐selectin) and tumour necrosis factor α (TNFα) showed the strongest association with haem‐related parameters and soluble intercellular adhesion molecule 1 (sICAM‐1), sVCAM‐1, interleukin 6 (IL‐6) and vascular endothelial growth factor (VEGF) with iron‐related parameters. While hereditary spherocytosis was associated with the highest IL‐6 and TNFα levels, β‐thalassaemia major showed limited inflammation compared to SCD. The sVCAM1 increase was significantly lower in patients with SCD receiving exchange compared to simple transfusions. The present results support the involvement of free haem/iron species in the pathogenesis of vascular dysfunction and sterile inflammation in haemolytic diseases, irrespective of the underlying haemolytic mechanism, and highlight the potential therapeutic benefit of iron/haem scavenging therapies in these conditions. [ABSTRACT FROM AUTHOR]

Contamination of drinking water by per- and polyfluoroalkyl substances (PFASs) emitted from manufacturing plants, fire-fighting foams, and urban waste streams has received considerable attention due to concerns over toxicity and environmental persistence; however, PFASs in ambient air remain poorly understood, especially in the United States (US). We measured PFAS concentrations in ambient fine particulate matter (PM2.5) at 5 locations across North Carolina over a 1 year period in 2019. Thirty-four PFASs, including perfluoroalkyl carboxylic, perfluoroalkane sulfonic, perfluoroalkyl ether carboxylic and sulfonic acids were analyzed by UHPLC/ESI-MS/MS. Quarterly averaged concentrations ranged from <0.004–14.1 pg m−3. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) ranged from <0.18 to 14.1 pg m−3, comparable to previous PM2.5 measurements from Canada and Europe (<0.02–3.5 pg m−3). Concentrations above 1 pg m−3 were observed in July–September at Charlotte (14.1 pg m−3, PFOA), Wilmington (4.75 pg m−3, PFOS), and Research Triangle Park (1.37 pg m−3, PFOS). Notably, PM2.5 has a short atmospheric lifetime (<2 weeks), and thus, the presence of PFOS in these samples raises questions about their sources, since PFOS production was phased out in the US ∼20 years ago. This is the first US study to provide insights into ambient PFAS concentrations in PM2.5. [ABSTRACT FROM AUTHOR]