The Lateral Continuity and Vertical Arrangement of Dust Layers in the Martian North Polar Cap From SHARAD Multiband Data.

Interpretation of radar sounder reflections to infer the structure and composition of the martian polar caps depends on whether bright returns correspond to single packed dust layers or a more finely layered structure. Reflections from multiple layers can create strong resonant scattering (interference) effects that impact analyses of radargram reflectors and inference of dielectric contrast. We identify resonant behavior for an areally extensive reflector in the north polar layered deposits from Shallow Radar data processed in two frequency bands. Echo strength varies by ∼2 dB between subband reflections across a region ∼400 km in extent, with the stronger echo shifting abruptly from the high- to low-frequency band outside the central region of Gemina Lingula. This behavior can arise from resonant scattering between two layers of dust (0.3-0.6 m thick) separated by 0.5-3 m of ice. Such layering requires there be little postdepositional aeolian activity to preserve layer thickness and spacing.

FIRE - Flyby of Io with Repeat Encounter: A conceptual design for a New Frontiers mission to Io.

A conceptual design is presented for a low complexity, heritage-based flyby mission to Io, Jupiter's innermost Galilean satellite and the most volcanically active body in the Solar System. The design addresses the 2011 Decadal Surveys recommendation for a New Frontiers class mission to Io and is based upon the result of the June 2012 NASA-JPL Planetary Science Summer School. A science payload is proposed to investigate the link between the structure of Io's interior, it's volcanic activity, it's surface composition, and it's tectonics. A study of Io's atmospheric processes and Io's role in the Jovian magnetosphere is also planned. The instrument suite includes a visible/near IR imager, a magnetic field and plasma suite, a dust analyzer and a gimbaled high gain antenna to perform radio science investigations. Payload activity and spacecraft operations would be powered by three Advanced Stirling Radioisotope Generators (ASRG). The primary mission includes 10 flybys with close-encounter altitudes as low as 100 km. The mission risks are mitigated by ensuring that relevant components are radiation tolerant and by using redundancy and flight-proven parts in the design. The spacecraft would be launched on an Atlas V rocket with a delta-v of 1.3 km/s. Three gravity assists (Venus, Earth, Earth) would be used to reach the Jupiter system in a 6-year cruise. The resulting concept demonstrates the rich scientific return of a flyby mission to Io.

Patient-Reported Outcomes in Long-Term Survivors of Autologous Hematopoietic Cell Transplantation in Multiple Myeloma.

The overall survival in patients with transplantation-eligible multiple myeloma has tripled over the past 2 decades, leading to a growing population of myeloma survivors. However, there is a paucity of data on health-related quality of life (HRQoL), distress, and health behaviors in long-term myeloma survivors who are in stable remission after autologous hematopoietic cell transplantation (AHCT). In this cross-sectional study using data from 2 randomized controlled trials of survivorship care plans and internet-based self-management intervention in transplantation survivors, the primary objective was to measure HRQoL (using the Short Form-12, version 2.0 [SF-12 v2]), distress (using the Cancer- and Treatment-Related Distress [CTXD] instrument), and health behaviors of myeloma survivors in stable remission after AHCT. A total of 345 patients at a median of 4 years (range, 1.4 to 11 years) post-AHCT were included. The mean SF-12 v2 Physical Component Summary (PCS) score was 45.5 ± 10.5, and the mean Mental Component Summary (MCS) score was 51.3 ± 10.1, compared with US population norms of 50 ± 10 for both (P < .001 and P = .021 for PCS and MCS comparisons, respectively). Notably, neither reached the threshold for a minimal clinically important difference. Approximately one-third of the patients had clinically significant distress based on the CTXD total score, with distress reported by 53% of the patients in the Health Burden domain, by 46% in the Uncertainty domain, by 33% in the Finances domain, by 31% in the Family Strain domain, by 21% in the Identity domain, and by 15% in the Medical Demands domain. Preventive care guidelines were adhered to by 81% of the myeloma survivors; however, adherence to exercise and diet guidelines were relatively low, at 33% and 13%, respectively. Myeloma AHCT survivors in stable remission have no clinically meaningful worsening in physical functioning compared with the general population. Survivorship programs should address ongoing distress due to health burden, uncertainty, and finances in myeloma survivors, along with evidence-based targeted interventions for modifiable health behaviors, such as nutrition and exercise.

Pyroclastic Flow Deposits on Venus as Indicators of Renewed Magmatic Activity.

Radar-bright deposits on Venus that have diffuse margins suggest eruptions that distribute debris over large areas due to ground-hugging flows from plume collapse. We examine deposits in Eastern Eistla, Western Eistla, Phoebe, and Dione Regiones using Magellan data and Earth-based radar maps. The radar-bright units have no marginal lobes or other features consistent with viscous flow. Their morphology, radar echo strength, polarization properties, and microwave emissivity are consistent with mantling deposits comprised of few-cm or larger clasts. This debris traveled downhill up to ~100 km on modest slopes, and blanketed lava flows and tectonic features to depths of tens of cm to a few meters over areas up to 40×103 km2. There is evidence for ongoing removal and exhumation of previously buried terrain. A newly identified occurrence is associated with a ridge belt south of Ushas Mons. We also note radar-bright streaks of coarse material west of Rona Chasma that reflect the last traces of a deposit mobilized by winds from the formation of Mirabeau crater. If the radar-bright units originate by collapse of eruption columns, with coarse fragmental material entrained and fluidized by hot gases, then their extent suggests large erupted volatile (CO2 or H2O) amounts. We propose that these deposits reflect the early stage of renewed magmatic activity, with volatile-rich, disrupted magma escaping through vents in fractured regions of the upper crust. Rapidly eroding under Venus surface conditions, or buried by subsequent eruptions, these markers of recently renewed activity have disappeared from older regions.

Development and Validation of a Novel Acute Myeloid Leukemia-Composite Model to Estimate Risks of Mortality.

Importance: To our knowledge, this multicenter analysis is the first to test and validate (1) the prognostic impact of comorbidities on 1-year mortality after initial therapy of acute myeloid leukemia (AML) and (2) a novel, risk-stratifying composite model incorporating comorbidities, age, and cytogenetic and molecular risks. Objective: To accurately estimate risks of mortality by developing and validating a composite model that combines the most significant patient-specific and AML-specific features. Design, Setting, and Participants: This is a retrospective cohort study. A series of comorbidities, including those already incorporated into the hematopoietic cell transplantation­comorbidity index (HCT-CI), were evaluated. Patients were randomly divided into a training set (n = 733) and a validation set (n = 367). In the training set, covariates associated with 1-year overall mortality at a significance level of P < .10 constructed a multivariate Cox proportional hazards model in which the impact of each covariate was adjusted for that of all others. Then, the adjusted hazard ratios were used as weights. Performances of models were compared using C statistics for continuous outcomes and area under the curve (AUC) for binary outcomes. Exposures: Initial therapy for AML. Main Outcomes and Measures: Death within 1 year after initial therapy for AML. Results: A total of 1100 patients, ages 20 to 89 years, were treated for AML between January 1, 2008, and December 31, 2012, at 5 academic institutions specialized in treating AML; 605 (55%) were male, and 495 (45%) were female. In the validation set, the original HCT-CI had better C statistic and AUC estimates compared with the AML comorbidity index for prediction of 1-year mortality. Augmenting the original HCT-CI with 3 independently significant comorbidities, hypoalbuminemia, thrombocytopenia, and high lactate dehydrogenase level, yielded a better C statistic of 0.66 and AUC of 0.69 for 1-year mortality. A composite model comprising augmented HCT-CI, age, and cytogenetic/molecular risks had even better predictive estimates of 0.72 and 0.76, respectively. Conclusions and Relevance: In this cohort study, comorbidities influenced 1-year survival of patients with AML, and comorbidities are best captured by an augmented HCT-CI. The augmented HCT-CI, age, and cytogenetic/molecular risks could be combined into an AML composite model that could guide treatment decision-making and trial design in AML. Studying physical, cognitive, and social health might further clarify the prognostic role of aging. Targeting comorbidities with interventions alongside specific AML therapy might improve survival.

Flood volcanism in the northern high latitudes of Mercury revealed by MESSENGER.

MESSENGER observations from Mercury orbit reveal that a large contiguous expanse of smooth plains covers much of Mercury's high northern latitudes and occupies more than 6% of the planet's surface area. These plains are smooth, embay other landforms, are distinct in color, show several flow features, and partially or completely bury impact craters, the sizes of which indicate plains thicknesses of more than 1 kilometer and multiple phases of emplacement. These characteristics, as well as associated features, interpreted to have formed by thermal erosion, indicate emplacement in a flood-basalt style, consistent with x-ray spectrometric data indicating surface compositions intermediate between those of basalts and komatiites. The plains formed after the Caloris impact basin, confirming that volcanism was a globally extensive process in Mercury's post-heavy bombardment era.