In Earth's deep continental subsurface, where groundwaters are often isolated for >106 to 109 years, energy released by radionuclides within rock produces oxidants and reductants that drive metabolisms of non-photosynthetic microorganisms. Similar processes could support past and present life in the martian subsurface. Sulfate-reducing microorganisms are common in Earth's deep subsurface, often using hydrogen derived directly from radiolysis of pore water and sulfate derived from oxidation of rock-matrix-hosted sulfides by radiolytically derived oxidants. Radiolysis thus produces redox energy to support a deep biosphere in groundwaters isolated from surface substrate input for millions to billions of years on Earth. Here, we demonstrate that radiolysis by itself could produce sufficient redox energy to sustain a habitable environment in the subsurface of present-day Mars, one in which Earth-like microorganisms could survive wherever groundwater exists. We show that the source localities for many martian meteorites are capable of producing sufficient redox nutrients to sustain up to millions of sulfate-reducing microbial cells per kilogram rock via radiolysis alone, comparable to cell densities observed in many regions of Earth's deep subsurface. Additionally, we calculate variability in supportable sulfate-reducing cell densities between the martian meteorite source regions. Our results demonstrate that martian subsurface groundwaters, where present, would largely be habitable for sulfate-reducing bacteria from a redox energy perspective via radiolysis alone. We present evidence for crustal regions that could support especially high cell densities, including zones with high sulfide concentrations, which could be targeted by future subsurface exploration missions.There is a growing need for valid and reliable measures to monitor the efficacy of undergraduate science, technology, engineering, and mathematics (STEM) reform initiatives. The Classroom Observation Protocol for Undergraduate STEM (COPUS) is a widely used tool originally designed to measure the presence of overt instructor and student behaviors. It has subsequently been used to characterize instruction along a continuum from didactic to student centered, and more recently to categorize instruction into one of three styles. Initiatives focused on professional development often support instructors' progression from didactic to student-centered styles. There is a need to examine COPUS instructional styles in terms of behaviors that research has shown to improve student learning. Formative assessment is a research-based practice that involves behaviors accounted for by the COPUS (e.g., posing a question). We qualitatively compared the formative assessment behaviors in 16 biology class sessions categorized into each of the three COPUS styles. We were unable to detect differences in formative assessment behaviors between the COPUS styles. Caution should be taken when interpreting COPUS data to make inferences about the effects of reform efforts. This study underscores the need for additional measures to monitor national reform initiatives in undergraduate STEM.Student-centered teaching practices such as active learning continue to gain momentum in college science education. Many instructors committed to these innovative practices transform their classrooms beyond the standard lecture. Nevertheless, widespread implementation of these practices is limited, because the learning benefits for students are often attained through increased instructional complexity to which many instructors cannot commit. When co-instructors are teaching the course, the level of commitment to building a student-centered classroom may be even more profound. For these reasons, new tools are needed to help instructors and co-instructors plan, organize, evaluate, and communicate their classroom innovations. Pathway modeling is a tool with the potential to fill this gap. https://www.selleckchem.com/products/mt-802.html Unlike curriculum mapping-which identifies academic content gaps, redundancies, and misalignments by examining a series of courses within a plan of study-course pathway modeling creates a visual map of a single course and reveals how teaching practices influence short-, mid-, and long-term student learning outcomes. This essay demonstrates how course pathway modeling can help co-instructors better represent the complexity of student-centered teaching practices. We include guides for creating course pathway models and discuss how this approach offers the potential to improve curricular design, course evaluation, student assessment, and communication between co-instructors.Heart failure affects 1-2% of the adult population and one of the main contributors to its development is cardiomyopathy. Assessing a patient's risk for adverse events in heart failure is challenging and made more difficult by the heterogenous phenotypic expression of the disease. Cardiac MRI has long been a gold standard measure of myocardial function and anatomy due to its high spatial and temporal resolution. More recently, it has been posited to play a more critical role in the diagnosis and prognosis of cardiomyopathy-related heart failure. Given the limitations of more commonly used imaging modalities, increasing the clinical use of cardiac magnetic resonance imaging could potentially improve the prognosis of specific subgroups of patients at risk of adverse cardiac events.Preferential uptake of either levorotatory (L) or dextrorotatory (D) enantiomer of a chiral molecule is a potential planetary life-detection method. On Earth, bacteria, as a rule, metabolize D-sugars and L-amino acids. Here, we use growth experiments to identify exceptions to the rule and their potential impact on the method's reliability. Our experiments involve six strains of Bacillus and collective uptake of the sugars glucose and arabinose, and the amino acids alanine, glutamic acid, leucine, cysteine, and serine-all of which are highly soluble. We find that selective uptake is not evident unless (1) each sugar is tested individually and (2) multiple amino acids are tested together in a mixture. Combining sugars should be avoided because, as we show in Bacillus bacteria, the same organisms may catabolize one sugar, glucose, in D-form and another sugar, arabinose, in L-form. Single amino acids should be avoided because bacteria can access certain proteinogenically incompatible enantiomers using specific racemases.