Astronomical Observations in Support of Planetary Entry-Probes to the Outer Planets.

A team of Earth-based astronomical observers supporting a giant planet entry-probe event substantially enhances the scientific return of the mission. An observers' team provides spatial and temporal context, additional spectral coverage and resolution, viewing geometries that are not available from the probe or the main spacecraft, tracking, supporting data in case of a failure, calibration benchmarks, and additional opportunities for education and outreach. The capabilities of the support program can be extended by utilizing archived data. The existence of a standing group of observers facilitates the path towards acquiring Director's Discretionary Time at major telescopes, if, for example, the probe's entry date moves. The benefits of a team convened for a probe release provides enhanced scientific return throughout the mission. Finally, the types of observations and the organization of the teams described in this paper could serve as a model for flight projects in general.

Origin and Evolution of Enceladus's Tidal Dissipation.

Enceladus possesses a subsurface ocean beneath a conductive ice shell. Based on shell thickness models, the estimated total conductive heat loss from Enceladus is 25-40 GW; the measured heat output from the South Polar Terrain (SPT) is 4-19 GW. The present-day SPT heat flux is of order 100 mWm-2, comparable to estimated paleo-heat fluxes for other regions of Enceladus. These regions have nominal ages of about 2 Ga, but the estimates are uncertain because the impactor flux in the Saturnian system may not resemble that elsewhere. Enceladus's measured rate of orbital expansion implies a low dissipation factor Qp for Saturn, with Qp≈3×103 (neglecting the role of Dione). This value implies that Enceladus's present-day equilibrium tidal heat production (roughly 50 GW, but with large uncertainties) is in approximate balance with its heat loss. If Qp is constant, Enceladus cannot be older than 1.5 Gyr (because otherwise it would have migrated more than is permissible). However, Saturn's dissipation may be better described by the "resonance-locking" theory, in which case Enceladus's orbit may have only evolved outwards by about 35% over the age of the Solar System. In the constant-Qp scenario, any ancient tidal heating events would have been too energetic to be consistent with the observations. Because resonance-locking makes capture into earlier mean-motion orbital resonances less likely, the inferred ancient heating episodes probably took place when the current orbital resonance was already established. In the resonance-locking scenario, tidal heating did not change significantly over time, allowing for a long-lived ocean and a relatively stable ice shell. If so, Enceladus is an attractive target for future exploration from a habitability standpoint.

Quantitative Analysis of Isoform Switching in Cancer.

Over the past 8 years, multiple studies examined the phenomenon of isoform switching in human cancers and discovered that isoform switching is widespread, with hundreds to thousands of such events per cancer type. Although all of these studies used slightly different definitions of isoform switching, which in part led to a rather poor overlap of their results, they all leveraged transcript usage, a proportion of the transcript's expression in the total expression level of the parent gene, to detect isoform switching. However, how changes in transcript usage correlate with changes in transcript expression is not sufficiently explored. In this article, we adopt the most common definition of isoform switching and use a state-of-the-art tool for the analysis of differential transcript usage, SatuRn, to detect isoform switching events in 12 cancer types. We analyze the detected events in terms of changes in transcript usage and the relationship between transcript usage and transcript expression on a global scale. The results of our analysis suggest that the relationship between changes in transcript usage and changes in transcript expression is far from straightforward, and that such quantitative information can be effectively used for prioritizing isoform switching events for downstream analyses.

Spinal cord injury - assessing tolerability and use of combined rehabilitation and NeuroAiD (SATURN) study - primary results of an exploratory study.

OBJECTIVE: MLC601/MLC901 has demonstrated neuroprotective and neuroregenerative properties that enhance neurological recovery in stroke and traumatic brain injury. We aimed to evaluate its safety and potential efficacy in patients with severe spinal cord injury. METHODS: Patients with American Spinal Injury Association (ASIA) Impairment Scale (AIS) A and B were included in an open-label cohort study. Each received a course of MLC601/MLC901 for 6 months in addition to standard care and rehabilitation. Key endpoints were safety, AIS grade and motor scores at month 6 (M6). RESULTS: Among 30 patients included (mean age 42.2 ± 17.6 years, 24 men), 20 patients had AIS A while 10 patients had AIS B at baseline. Ten patients experienced 14 adverse events including one serious adverse event and six deaths, none were considered treatment-related. AIS improved in 25% of AIS A and 50% of AIS B. Improvement in ASIA motor score was seen most with cervical injury (median change from baseline 26.5, IQR: 6-55). These findings appear to be better than reported rates of spontaneous recovery for SCI AIS A and B. CONCLUSION: MLC601/MLC901 is safe and may have a role in the treatment of patients with SCI. A controlled trial is justified.

Acceleration of Electrons by Whistler-Mode Hiss Waves at Saturn.

Plasmaspheric hiss waves at the Earth are well known for causing losses of electrons from the radiation belts through wave particle interactions. At Saturn, however, we show that the different plasma density environment leads to acceleration of the electrons rather than loss. The ratio of plasma frequency to electron gyrofrequency frequently falls below one creating conditions for hiss to accelerate electrons. The location of hiss at high latitudes (>25°) coincides very well with this region of very low density. The interaction between electrons and hiss only occurs at these higher latitudes, therefore the acceleration is limited to mid to low pitch angles leading to butterfly pitch angle distributions. The hiss is typically an order of magnitude stronger than chorus at Saturn and the resulting acceleration is rapid, approaching steady state in one day at 0.4 MeV at L = 7 and the effect is stronger with increasing L-shell.

Energy Exchanges in Saturn's Polar Regions From Cassini Observations: Eddy-Zonal Flow Interactions.

Saturn's polar regions (polewards of ∼63° planetocentric latitude) are strongly dynamically active with zonal jets, polar cyclones and the intriguing north polar hexagon (NPH) wave. Here we analyze measurements of horizontal winds, previously obtained from Cassini images by Antuñano et al. (2015), https://doi.org/10.1002/2014je004709, to determine the spatial and spectral exchanges of kinetic energy (KE) between zonal mean zonal jets and nonaxisymmetric eddies in Saturn's polar regions. Eddies of most resolved scales generally feed KE into the eastward and westward zonal mean jets at rates between 4.3 × 10-5 and 1.4 × 10-4 W kg-1. In particular, the north polar jet (at 76°N) was being energized at a rate of ∼10-4 W kg-1, dominated by the contribution due to the zonal wavenumber m = 6 NPH wave itself. This implies that the hexagon was not being driven at this time through a barotropic instability of the north polar jet, but may suggest a significant role for baroclinic instabilities, convection or other internal energy sources for this feature. The south polar zonal mean jet KE was also being sustained by eddies in that latitude band across a wide range of m. In contrast, results indicate that the north polar vortex may have been weakly barotropically unstable at this time with eddies of low m gaining KE at the expense of the axisymmetric cyclone. However, the southern axisymmetric polar cyclone was gaining KE from non-axisymmetric components at this time, including m = 2 and its harmonics, as the elliptical distortion of the vortex may have been decaying.

HbA1c, Coronary atheroma progression and cardiovascular outcomes.

BACKGROUND AND AIMS: We tested the hypothesis that on-treatment HbA1c levels independently associate with coronary atheroma progression and major adverse cardiovascular events (MACE: death, myocardial infarction, cerebrovascular accident, coronary revascularization, or hospitalization for unstable angina) rates. METHODS: We performed a post-hoc pooled analysis of data from seven prospective, randomized trials involving serial coronary intravascular ultrasonography (IVUS). The percent atheroma volume (PAV) was calculated as the proportion of the entire vessel wall occupied by atherosclerotic plaque. Using multivariable mixed modeling, we determined the association of on-treatment HbA1c with annualized change in PAV. Cox proportional hazard models were used to assess the association of HbA1c with incidence of MACE. RESULTS: Among 3,312 patients (mean age 58.6±9years, 28.4%women) average on-treatment HbA1c was 6.2±1.1%. Overall, there was no net significant annualized change in PAV (0.12±0.19%, p = 0.52). In a fully adjusted multivariable analysis (following adjustment of age, sex, body mass index, systolic blood pressure, smoking, low- and high-density lipoprotein cholesterol, triglyceride levels, peripheral vascular disease, trial, region, and baseline PAV), higher on-treatment HbA1c levels were independently associated with annualized changes in PAV [beta-estimate (95% confidence interval): 0.13(0.08, 0.19), p < 0.001]. On-treatment HbA1c levels were independently associated with MACE [hazard ratio (95% confidence interval): 1.13(1.04, 1.23), p = 0.005]. CONCLUSIONS: Independent of achieved cardiovascular risk factor control, greater HbA1c levels significantly associate with coronary atheroma progression rates and clinical outcomes. These results support the notion of a direct, specific effect of glycemic control upon coronary atheroma and atherosclerotic events, supporting the rationale of therapies designed to directly modulate it.

Long-term monitoring of soil bulk density and erosion rates in two Prunus Persica (L) plantations under flood irrigation and glyphosate herbicide treatment in La Ribera district, Spain.

Early season fruit production for the northern European market is highly intensive in fertilization, machinery, irrigation and the use of herbicides. Those conditions increase the soil losses and soil compaction and threaten the Sustainable Goals for Development of the United Nations by 2030. Long-term soil erosion measurements are necessary to determine the sustainability of agriculture managements. Moreover, soil erosion on flood irrigation land is a topic that request more surveys and research as rainfed sloping terrains attracted all the attention of scientists and research investment. Improved Stock Unearthing Method (ISUM) was applied to two 15 years-old herbicide treated fields of Saturn peaches (Prunus persica var. platycarpa) to determine long-term soil erosion rates (2004-2019). Using ISUM, a 1 mm thick nylon rope (700 mm length) was used to connect trees perpendicular to the direction of rows at the height of the graft. To detection soil lowering, the vertical distance of the rope to the soil surface was measured at 10 cm intervals along the rope. The ring method (264 samples at 0-6 cm) was used to determine the soil bulk density, which was in average 1.15 gr cm-3 for both plots. There was found a compaction in the centre of both plots due to the pass of machinery with mean bulk density values of 1.23 gr cm-3, meanwhile underneath of the trees, the soil bulk density was 1.05 gr cm-3. The topography survey carried out with ISUM (2508 sampling points) informed that flood irrigation redistributed the soil from the upper to the lower field position, where a sedimentation layer was measured. We found that the two studied fields showed a contrasted response, with low soil erosion values in Benimodo and high in L'Alcúdia study sites. Soil erosion rates were in average 1.46 Mg ha-1 yr-1 and 8.02 Mg ha-1 yr-1 for Benimodo and L'Alcúdia, respectively. However, the maps development using ISUM allow to inform that the pattern of soil redistribution is similar for both fields as the highest soil lowering was found in the upper field part, where the flood discharge detach soil particles. In the lower field position sedimentation takes place. The dataset allows us to conclude that soil erosion in Saturn peaches fields is non-sustainable and more soil conservation management should be applied to reduce the soil erosion rates due to the bare soils as a consequence of the use of herbicides. This research informs that soil erosion in flood irrigated fields is a relevant process that needs more investigations around the world, where 94% of the irrigated land is under flood or furrow irrigation, and where irrigation is growing year after year.

satuRn: Scalable analysis of differential transcript usage for bulk and single-cell RNA-sequencing applications.

Alternative splicing produces multiple functional transcripts from a single gene. Dysregulation of splicing is known to be associated with disease and as a hallmark of cancer. Existing tools for differential transcript usage (DTU) analysis either lack in performance, cannot account for complex experimental designs or do not scale to massive single-cell transcriptome sequencing (scRNA-seq) datasets. We introduce satuRn, a fast and flexible quasi-binomial generalized linear modelling framework that is on par with the best performing DTU methods from the bulk RNA-seq realm, while providing good false discovery rate control, addressing complex experimental designs, and scaling to scRNA-seq applications.

Topography and geology of Uranian mid-sized icy satellites in comparison with Saturnian and Plutonian satellites.

Newly processed global imaging and topographic mapping of Uranus's five major satellites reveal differences and similarities to mid-sized satellites at Saturn and Pluto. Three modes of internal heat redistribution are recognized. The broad similarity of Miranda's three oval resurfacing zones to those mapped on Enceladus and (subtly) on Dione are likely due to antipodal diapiric upwelling. Conversely, break-up and foundering of crustal blocks accompanied by extensive (cryo)volcanism is the dominant mode on both Charon and Ariel. Titania's fault network finds parallels on Rhea, Dione, Tethys and possibly Oberon. Differences in the geologic style of resurfacing in the satellite systems (e.g. plains on Charon, Dione, Tethys and perhaps Titania versus ridges on Miranda and Ariel) may be driven by differences in ice composition. Surface processes such as volatile transport may also be indicated by bright and dark materials on Oberon, Umbriel and Charon. The more complete and higher quality observations of the Saturnian and Plutonian mid-sized icy satellites by Cassini and New Horizons reveal a wealth of features and phenomena that cannot be perceived in the more limited Voyager coverage of the Uranian satellites, harbingers of many discoveries awaiting us on a return to Uranus. This article is part of a discussion meeting issue 'Future exploration of ice giant systems'.

One small step? Collection strategies for libraries, archives, and museums in the space age.

This article will compare the collection of materials for the Saturn V documentation project under NAS8-21321 in 1968 to standard processes for collecting space history today. A case study of The Saturn V grant outlines the benefits of collecting research material in real time. This case study is compared to the findings compiled at the 2018 conference "To Boldly Preserve: Archiving for the Next Half-Century of Spaceflight." The findings of this conference found that collecting space history is often fragmented by three factors: early space actors are in the twilight of their careers and loss of historical memories and materials is imminent, there is a vast expansion of the number of actors in the space industry which makes collection more difficult, and that the digital age has changed both the nature of the material and the methods by which LAMS collect them. Libraries, Archives, and Museums (LAMs) can and should develop a collaborative approach to collecting space history and ensure that acquisition and preservation of these materials goes beyond one small step and is instead one giant leap.

Cassini Exploration of the Planet Saturn: A Comprehensive Review.

Before Cassini, scientists viewed Saturn's unique features only from Earth and from three spacecraft flying by. During more than a decade orbiting the gas giant, Cassini studied the planet from its interior to the top of the atmosphere. It observed the changing seasons, provided up-close observations of Saturn's exotic storms and jet streams, and heard Saturn's lightning, which cannot be detected from Earth. During the Grand Finale orbits, it dove through the gap between the planet and its rings and gathered valuable data on Saturn's interior structure and rotation. Key discoveries and events include: watching the eruption of a planet-encircling storm, which is a 20- or 30-year event, detection of gravity perturbations from winds 9000 km below the tops of the clouds, demonstration that eddies are supplying energy to the zonal jets, which are remarkably steady over the 25-year interval since the Voyager encounters, re-discovery of the north polar hexagon after 25 years, determination of elemental abundance ratios He/H, C/H, N/H, P/H, and As/H, which are clues to planet formation and evolution, characterization of the semiannual oscillation of the equatorial stratosphere, documentation of the mysteriously high temperatures of the thermosphere outside the auroral zone, and seeing the strange intermittency of lightning, which typically ceases to exist on the planet between outbursts every 1-2 years. These results and results from the Jupiter flyby are all discussed in this review.

Incorporating Physical Knowledge Into Machine Learning for Planetary Space Physics.

Recent improvements in data collection volume from planetary and space physics missions have allowed the application of novel data science techniques. The Cassini mission for example collected over 600 gigabytes of scientific data from 2004 to 2017. This represents a surge of data on the Saturn system. In comparison, the previous mission to Saturn, Voyager over 20 years earlier, had onboard a ~70 kB 8-track storage ability. Machine learning can help scientists work with data on this larger scale. Unlike many applications of machine learning, a primary use in planetary space physics applications is to infer behavior about the system itself. This raises three concerns: first, the performance of the machine learning model, second, the need for interpretable applications to answer scientific questions, and third, how characteristics of spacecraft data change these applications. In comparison to these concerns, uses of "black box" or un-interpretable machine learning methods tend toward evaluations of performance only either ignoring the underlying physical process or, less often, providing misleading explanations for it. The present work uses Cassini data as a case study as these data are similar to space physics and planetary missions at Earth and other solar system objects. We build off a previous effort applying a semi-supervised physics-based classification of plasma instabilities in Saturn's magnetic environment, or magnetosphere. We then use this previous effort in comparison to other machine learning classifiers with varying data size access, and physical information access. We show that incorporating knowledge of these orbiting spacecraft data characteristics improves the performance and interpretability of machine leaning methods, which is essential for deriving scientific meaning. Building on these findings, we present a framework on incorporating physics knowledge into machine learning problems targeting semi-supervised classification for space physics data in planetary environments. These findings present a path forward for incorporating physical knowledge into space physics and planetary mission data analyses for scientific discovery.

Rapid Electron Acceleration in Low-Density Regions of Saturn's Radiation Belt by Whistler Mode Chorus Waves.

Electron acceleration at Saturn due to whistler mode chorus waves has previously been assumed to be ineffective; new data closer to the planet show it can be very rapid (factor of 104 flux increase at 1 MeV in 10 days compared to factor of 2). A full survey of chorus waves at Saturn is combined with an improved plasma density model to show that where the plasma frequency falls below the gyrofrequency additional strong resonances are observed favoring electron acceleration. This results in strong chorus acceleration between approximately 2.5 R S and 5.5 R S outside which adiabatic transport may dominate. Strong pitch angle dependence results in butterfly pitch angle distributions that flatten over a few days at 100s keV, tens of days at MeV energies which may explain observations of butterfly distributions of MeV electrons near L=3. Including cross terms in the simulations increases the tendency toward butterfly distributions.

Local-time averaged maps of H3+ emission, temperature and ion winds.

We present Keck-NIRSPEC observations of Saturn's [Formula: see text] aurora taken over a period of a month, in support of the Cassini mission's 'Grand Finale'. These observations produce two-dimensional maps of Saturn's [Formula: see text] temperature and ion winds for the first time. These maps show surprising complexity, with different morphologies seen in each night. The [Formula: see text] ion winds reveal multiple arcs of 0.5-1 km s-1 ion flows inside the main auroral emission. Although these arcs of flow occur in different locations each night, they show intricate structures, including mirrored flows on the dawn and dusk of the planet. These flows do not match with the predicted flows from models of either axisymmetric currents driven by the Solar Wind or outer magnetosphere, or the planetary periodic currents associated with Saturn's variable rotation rate. The average of the ion wind flows across all the nights reveals a single narrow and focused approximately 0.3 km s-1 flow on the dawn side and broader and more extensive 1-2 km s-1 sub-corotation, spilt into multiple arcs, on the dusk side. The temperature maps reveal sharp gradients in ionospheric temperatures, varying between 300 and 600 K across the auroral region. These temperature changes are localized, resulting in hot and cold spots across the auroral region. These appear to be somewhat stable over several nights, but change significantly over longer periods. The position of these temperature extremes is not well organized by the planetary period and there is no evidence for a thermospheric driver of the planetary period current system. Since no past magnetospheric or thermospheric models explain the rich complexity observed here, these measurements represent a fantastic new resource, revealing the complexity of the interaction between Saturn's thermosphere, ionosphere and magnetosphere. This article is part of a discussion meeting issue 'Advances in hydrogen molecular ions: H3+, H5+ and beyond'.

Identification of Plasma Waves at Saturn Using Convolutional Neural Networks.

Cassini has recently completed its 13-year mission at Saturn leaving a vast data set. A large interest among the scientific community is to investigate plasma waves and instabilities at Saturn. It is no longer feasible to manually search through Cassini's vast data set to identify all such waves of interest. Thus, the feasibility of using artificial neural networks (ANNs) to identify plasma waves at Saturn is demonstrated using Cassini data. A convolutional neural network (CNN) was trained to identify low-frequency plasma waves that occur in the upstream region of Saturn using images constructed from the Cassini magnetometer time series data. By systematically varying the network architecture during training and validation, a CNN was obtained that can identify upstream waves with an accuracy of 94% ± 2%. The CNN's high accuracy for wave identification demonstrates that it is, in fact, feasible to use ANNs to identify plasma waves at Saturn and by extension in other planetary and lunar plasma environments using spacecraft data.

A review of Morlet wavelet analysis of radial profiles of Saturn's rings.

Spiral waves propagating in Saturn's rings have wavelengths that vary with radial position within the disc. The best-quality observations of these waves have the form of radial profiles centred on a particular azimuth. In that context, the wavelength of a given spiral wave is seen to change substantially with position along the one-dimensional profile. In this paper, we review the use of Morlet wavelet analysis to understand these waves. When signal to noise is high and the cause of the wave is well understood, wavelet analysis has been used to solve for wave parameters that are diagnostic of local disc properties. Waves that are not readily perceptible in the spatial domain signal can be clearly identified. Furthermore, filtering in wavelet space, followed by the reverse wavelet transform, has been used to isolate the part of the signal that is of interest. When the cause of the wave is not known, comparing the phases of the complex-valued wavelet transforms from many profiles has been used to determine wave parameters that cannot be determined from any single profile. When signal to noise is low, co-adding wavelet transforms while manipulating the phase has been used to boost a wave's signal above detection limits.This article is part of the theme issue 'Redundancy rules: the continuous wavelet transform comes of age'.

Ground-based measurements of the 1.3 to 0.3 millimeter spectrum of Jupiter and Saturn, and their detailed calibration.

One of the legacies of the now retired Caltech Submillimeter Observatory (CSO) is presented in this paper. We measured for the first time the emission of the giant planets Jupiter and Saturn across the 0.3 to 1.3 mm wavelength range using a Fourier Transform Spectrometer mounted on the 10.4-meter dish of the CSO at Mauna Kea, Hawaii, 4100 meters above sea level. A careful calibration, including the evaluation of the antenna performance over such a wide wavelength range and the removal of the Earth's atmosphere effects, has allowed the detection of broad absorption lines on those planets' atmospheres. The calibrated data allowed us to verify the predictions of standard models for both planets in this spectral region, and to confirm the absolute radiometry in the case of Jupiter. Besides their physical interest, the results are also important as both planets are calibration references in the current era of operating ground-based and space-borne submillimeter instruments.

HIV drug resistance testing among patients failing second line antiretroviral therapy. Comparison of in-house and commercial sequencing.

INTRODUCTION: HIV genotyping is often unavailable in low and middle-income countries due to infrastructure requirements and cost. We compared genotype resistance testing in patients with virologic failure, by amplification of HIV pol gene, followed by "in-house" sequencing and commercial sequencing. METHODS: Remnant plasma samples from adults and children failing second-line ART were amplified and sequenced using in-house and commercial di-deoxysequencing, and analyzed in Harare, Zimbabwe and at Stanford, U.S.A, respectively. HIV drug resistance mutations were determined using the Stanford HIV drug resistance database. RESULTS: Twenty-six of 28 samples were amplified and 25 were successfully genotyped. Comparison of average percent nucleotide and amino acid identities between 23 pairs sequenced in both laboratories were 99.51 (±0.56) and 99.11 (±0.95), respectively. All pairs clustered together in phylogenetic analysis. Sequencing analysis identified 6/23 pairs with mutation discordances resulting in differences in phenotype, but these did not impact future regimens. CONCLUSIONS: The results demonstrate our ability to produce good quality drug resistance data in-house. Despite discordant mutations in some sequence pairs, the phenotypic predictions were not clinically significant.

Magnetic reconnection in Saturn's magnetotail: A comprehensive magnetic field survey.

Reconnection within planetary magnetotails is responsible for locally energizing particles and changing the magnetic topology. Its role in terms of global magnetospheric dynamics can involve changing the mass and flux content of the magnetosphere. We have identified reconnection related events in spacecraft magnetometer data recorded during Cassini's exploration of Saturn's magnetotail. The events are identified from deflections in the north-south component of the magnetic field, significant above a background level. Data were selected to provide full tail coverage, encompassing the dawn and dusk flanks as well as the deepest midnight orbits. Overall 2094 reconnection related events were identified, with an average rate of 5.0 events per day. The majority of events occur in clusters (within 3 h of other events). We examine changes in this rate in terms of local time and latitude coverage, taking seasonal effects into account. The observed reconnection rate peaks postmidnight with more infrequent but steady loss seen on the dusk flank. We estimate the mass loss from the event catalog and find it to be insufficient to balance the input from the moon Enceladus. Several reasons for this discrepancy are discussed. The reconnection X line location appears to be highly variable, though a statistical separation between events tailward and planetward of the X line is observed at a radial distance of between 20 and 30RS downtail. The small sample size at dawn prevents comprehensive statistical comparison with the dusk flank observations in terms of flux closure.