Paleoproterozoic snowball Earth: Extreme climatic and geochemical global change and its biological consequences

Geological, geophysical, and geochemical data support a theory that Earth experienced several intervals of intense, global glaciation (“snowball Earth” conditions) during Precambrian time. This snowball model predicts that postglacial, greenhouse-induced warming would lead to the deposition of banded iron formations and cap carbonates. Although global glaciation would have drastically curtailed biological productivity, melting of the oceanic ice would also have induced a cyanobacterial bloom, leading to an oxygen spike in the euphotic zone and to the oxidative precipitation of iron and manganese. A Paleoproterozoic snowball Earth at 2.4 Giga-annum before present (Ga) immediately precedes the Kalahari Manganese Field in southern Africa, suggesting that this rapid and massive change in global climate was responsible for its deposition. As large quantities of O(2) are needed to precipitate this Mn, photosystem II and oxygen radical protection mechanisms must have evolved before 2.4 Ga. This geochemical event may have triggered a compensatory evolutionary branching in the Fe/Mn superoxide dismutase enzyme, providing a Paleoproterozoic calibration point for studies of molecular evolution

Improving the safety of chemotherapy administration: an oncology nurse-led failure mode and effects analysis

noPURPOSE/OBJECTIVES: To assess and improve the safety of hospital-based adult chemotherapy administration. DESIGN: Prospective, systems-focused clinical risk assessment. SETTING: An adult inpatient and outpatient oncology unit in a large urban hospital in the United Kingdom. SAMPLE: 8-person nurse-led multidisciplinary team, which included managerial staff and patient safety researchers. METHODS: Failure mode and effects analysis (FMEA), a prospective, systems-focused risk assessment methodology, was undertaken in biweekly team meetings and included mapping the chemotherapy administration process, identifying and numerically prioritizing potential errors (failure modes) for each process step, and generating remedial strategies to counteract them. MAIN RESEARCH VARIABLES: The analysis aimed to identify chemotherapy administration failure modes and to generate remedial strategies to address them. User feedback on the FMEA process also was collected. FINDINGS: Several specific chemotherapy failure modes were identified, the majority of which had not previously been recognized, and several novel strategies to counteract them were generated. Many of the strategies were specific, environment-focused actions, which are simple, quick, and inexpensive to implement; however, more substantive, longer-term initiatives also were generated. User feedback generally was very positive, and the process of undertaking the analysis improved multidisciplinary teamwork and communication. CONCLUSIONS: Although time and resource intensive, FMEA is a useful safety improvement tool. IMPLICATIONS FOR NURSING: Nurses should be aware of and informed about FMEA as a tool they can use in partnership with management and other disciplines to proactively and collectively improve the safety of high-risk oncology procedures such as chemotherapy administration