International Workshop on Developing Strategies for Monitoring Data-Limited Deepwater Demersal Line Fisheries in the Pacific Ocean by Ashley J Williams, Simon J Nicol, Nokome Bentley, Paul J. Starr ...et al is reviewed.
The Mars Science Laboratory Curiosity rover has explored over 400 m of vertical stratigraphy within Gale crater to date. These fluvio‐deltaic, lacustrine, and aeolian strata have been well‐documented ...by Curiosity's in situ and remote science instruments, including the Mast Camera (Mastcam) pair of multispectral imagers. Mastcam visible to near‐infrared spectra can broadly distinguish between iron phases and oxidation states, and in combination with chemical data from other instruments, Mastcam spectra can help constrain mineralogy, depositional origin, and diagenesis. However, no traverse‐scale analysis of Mastcam multispectral data has yet been performed. We compiled a database of Mastcam spectra from >600 multispectral observations and quantified spectral variations across Curiosity's traverse through Vera Rubin ridge (sols 0–2302). From principal component analysis and an examination of spectral parameters, we identified nine rock spectral classes and five soil spectral classes. Rock classes are dominated by spectral differences attributed to hematite and other oxides (due to variations in grain size, composition, and abundance) and are mostly confined to specific stratigraphic members. Soil classes fall along a mixing line between soil spectra dominated by fine‐grained Fe‐oxides and those dominated by olivine‐bearing sands. By comparing trends in soil versus rock spectra, we find that locally derived sediments are not significantly contributing to the spectra of soils. Rather, varying contributions of dark, mafic sands from the active Bagnold Dune field is the primary spectral characteristic of soils. These spectral classes and their trends with stratigraphy provide a basis for comparison in Curiosity's ongoing exploration of Gale crater.
Plain Language Summary
The Curiosity rover's Mastcam instrument is a pair of cameras that take images in visible and near‐infrared wavelengths. Mastcam spectra can distinguish between different types of iron‐bearing minerals. During Curiosity's traverse through a variety of sedimentary rock types in Gale crater, Mars, the rover has acquired more than 600 Mastcam multispectral observations, but no previous studies have analyzed the full data set. In this study, we compiled a database of Mastcam spectra from the first 2302 sols (Martian days) of Curisoity's mission and analyzed spectral trends across the traverse. We define nine classes of spectra for rocks and five classes of spectra for soils, and we observe that different classes occur in different locations. The major spectral differences are due to the mineral hematite and other iron oxides. By comparing the trends in rock spectra to nearby soils across the traverse, we find that the soils are not made of the same minerals as the local rocks, but are dominated by sands from the active Bagnold Dune field. These spectral classes and their trends will be a basis of comparison for Curiosity's ongoing exploration of Gale crater.
Key Points
The diversity in Mastcam multispectral data from sols 0–2302 is encapsulated by nine rock spectral classes and five soil spectral classes
The major spectral differences in Mastcam spectra across Curiosity's traverse are attributable to hematite and other Fe‐oxides
Comparisons of soil versus rock spectra indicate that locally‐derived sediments are not significantly contributing to the spectra of soils
The first samples collected by the Perseverance rover on the Mars 2020 mission were from the Maaz formation, a lava plain that covers most of the floor of Jezero crater. Laboratory analysis of these ...samples back on Earth would provide important constraints on the petrologic history, aqueous processes, and timing of key events in Jezero crater. However, interpreting these samples requires a detailed understanding of the emplacement and modification history of the Maaz formation. Here we synthesize rover and orbital remote sensing data to link outcrop‐scale interpretations to the broader history of the crater, including Mastcam‐Z mosaics and multispectral images, SuperCam chemistry and reflectance point spectra, Radar Imager for Mars' subsurface eXperiment ground penetrating radar, and orbital hyperspectral reflectance and high‐resolution images. We show that the Maaz formation is composed of a series of distinct members corresponding to basaltic to basaltic‐andesite lava flows. The members exhibit variable spectral signatures dominated by high‐Ca pyroxene, Fe‐bearing feldspar, and hematite, which can be tied directly to igneous grains and altered matrix in abrasion patches. Spectral variations correlate with morphological variations, from recessive layers that produce a regolith lag in lower Maaz, to weathered polygonally fractured paleosurfaces and crater‐retaining massive blocky hummocks in upper Maaz. The Maaz members were likely separated by one or more extended periods of time, and were subjected to variable erosion, burial, exhumation, weathering, and tectonic modification. The two unique samples from the Maaz formation are representative of this diversity, and together will provide an important geochronological framework for the history of Jezero crater.
Plain Language Summary
The Perseverance rover on the Mars 2020 mission is collecting samples from Jezero crater for potential return to Earth via Mars Sample Return, and the first samples collected by the rover were from the Maaz formation, a lava plain that covers much of the crater floor. These igneous samples can be used to date when the lavas crystallized and to better understand their subsequent interactions with water, both of which will be important for reconstructing the history of habitable environments in Jezero crater. In this study we use images and reflectance spectra from the rover and orbiters, along with ground penetrating radar from the rover, to determine the history of the Maaz formation lavas. We find evidence for significant erosion and weathering in between successive flows, suggesting that they were emplaced over a long period of time. Some of the lavas underlie the Jezero delta, and so their age will provide limits on the timing of lake activity in Jezero crater, while others retain craters, so their age will help to better understand crater density‐based age estimates for surfaces across Mars.
Key Points
The Maaz formation is a series of pyroxene‐ and plagioclase‐dominated lava flows on the Jezero crater floor with variable morphologies
Significant erosion and tectonism occurred during at least one flow hiatus, suggesting emplacement over an extended period of time
The crystallization ages of Maaz formation samples will help constrain the timing of delta activity and the global cratering chronology
In this book, faculty members from a wide range of disciplines reflect on how they engage their academic specializations to teach students about the science, politics, and ethics of climate change. ...The contributors provide methods, strategies, rationales, and theoretical justifications for teaching climate issues in the university.
Despite high initial response rates to platinum-based chemotherapy, most patients with advanced ovarian carcinoma die of drug-resistant disease. Drug resistance can be overcome in the hematologic ...malignancies and lymphomas with high-dose therapy and bone marrow transplantation (BMT) when used early, suggesting that this therapy may also be of value in ovarian carcinoma. As a prelude to the use of high-dose chemotherapy with BMT early in the management of advanced ovarian carcinoma, we evaluated a new high-dose regimen in patients with relapsed/refractory ovarian carcinoma to define toxicities and responses. Thirty patients were treated, of whom 20 were platinum resistant and 22 had >1 cm maximum diameter disease. They received mitoxantrone (75 mg/m2), carboplatin (1500 mg/m2), and cyclophosphamide (120 mg/kg), followed by an autologous BMT. Overall, 89% responded, with clinical complete responses seen in 88 vs 47% (P = 0.06) of platinum-sensitive vs -resistant disease. There was only one early death (3.3%) due to Aspergillus pneumonia. Median survival for all 30 patients was 29 months, and at 3 years 23% are alive without disease. There was a 10.1- vs 5.1-month progression-free survival for patients with platinum-sensitive versus -resistant disease, and at a median follow-up of 12 months, 80% of the platinum-sensitive patients are alive. This regimen is safe, and for platinum-sensitive disease appears superior to other salvage therapies. Its use should be explored earlier in the management of advanced ovarian carcinoma.
High response rates are seen in patients undergoing dose-intensive chemotherapy and autologous marrow transplantation due to the ability of the therapy to overcome inherent or acquired drug ...resistance. However, relapse rates are also high because this drug resistance reversal is incomplete. Because both P-glycoprotein- and platinum-induced resistance appear to be clinically important and can be reversed in vitro with a short exposure of cyclosporin A (CSA) at 2000 and 5000 ng/ml, respectively, we undertook a trial of high-dose chemotherapy with carboplatin (1500mg/m2), mitoxantrone (75 mg/m2), and cyclophosphamide (120 mg/kg) over a 5-day period combined with escalating doses of CSA. Thirty-seven patients with primarily breast cancer (61% doxorubicin resistant) and ovarian cancer (85% platinum resistant) were treated with CSA given as a bolus 18 h prior to chemotherapy, followed by a 5-day infusion at doses of 5.0-28.2 mg/kg/day and the chemotherapy. The maximum tolerated dose of CSA was a bolus of 5.5 mg/kg and an infusion of 15. 9 mg/kg/day, which gave a mean serum CSA level of 1544 ng/ml. The dose-limiting toxicity was severe mucositis and enteritis, leading to infectious complications. Nephrotoxicity was seen in 42% and, while usually mild and reversible, was fatal in two patients with pretreatment creatinine clearances h80 ml/min. Grade III-IV isolated hyperbilirubinemia was seen in 39%, but appeared to be of no clinical significance. The overall response rate for the 26 patients with measurable/evaluable disease was 73% and 63% for those with doxorubicin- or platinum-resistant disease. The median overall survival and progression-free survival for the group were 18.1 and 8. 0 months. The overall survival for the nine patients with doxorubicin-resistant breast cancer was 19.3 months. Although we did not achieve CSA levels needed to reverse platinum resistance in vivo, levels approaching those needed to reverse P-glycoprotein resistance were reached at the maximum tolerated dose. The strategy of combining dose intensity with drug resistance reversal deserves further study, especially with the advent of potentially less toxic agents available to reverse P-glycoprotein-mediated resistance.
