Morphology of the Planum Boreum basal unit, Mars, and constraints on the origin and timing of icy circumpolar deposits

textData from the Shallow Radar instrument on Mars Reconnaissance Orbiter have enabled detailed scientific exploration of martian ice. Orbital ground penetrating radar enabled scientists to study subsurface ice stratigraphy, to uncover the geologic structure of ice on Mars with remarkable results for the north pole. On the north pole of Mars sits a massive, approximately two kilometer thick, deposit of pure water ice. This deposit is underlain with a sand and ice mixture that reaches 1.5 km maximum thickness. This dissertation examines the nature of the old sand/ice mixture on Mars' north pole. We use this ice to identify early trends in deposition and erosion on Mars' north pole and ultimately to link ice rich deposits that are not part of the polar cap. This multi-part study endeavors to understand and constrain the drivers of Mars' polar ice deposition. With careful stratigraphic analysis we hypothesize that depositional regime has not changed drastically since the upper part of the sand and ice mixture was emplaced in Middle Amazonian time. Sediment supply became limited and ice more plentiful with respect to sand; however, deposition remained aeolian in nature. Additionally, our work finds evidence that circumpolar landforms are related to the central mass of ice on Planum Boreum. We present evidence supporting a coeval evolution of the circumpolar deposits and central Planum Boreum. We also present evidence that refutes these features being part of a more extensive ancient ice cap. This indicates that the processes occurring at Planum Boreum are likely mirrored in nearby landforms such as small craters and isolated ice wedges. This is fundamental to polar science, the processes occurring on Planum Boreum and the processes responsible for deposition of the north polar layered deposits can be analyzed at additional locations. Furthermore, we find that if a climate signal exists in the ice deposits, as has been postulated, these circumpolar features are likely to contain the same climate signal as the central ice cap. Thus, this work unifies the complexity of martian polar processes and suggests future avenues of research.Geological Science

Absence of complement-mediated events after protamine reversal of heparin anticoagulation

Protamine reversal of heparin anticoagulation is associated with adverse hemodynamic effects that may be attenuated with protamine pretreatment (PP). This study assesses the role of complement activation during these phenomena in adult cardiac surgery patients. Sixteen individuals undergoing cardiopulmonary bypass were given intravenous normal saline or protamine (2 mg/kg) as a randomized pretreatment prior to undergoing heparin anticoagulation (400 IU/kg), coronary artery revascularization, and subsequent reversal of the anticoagulated state with protamine (4 mg/kg). Blood pressure, pulmonary artery diastolic pressure (PAD), heart rate, and cardiac output (CO) were measured during and after pretreatment, prior to heparin reversal by protamine, and for 10 min after reversal. Total hemolytic complement (CH50), C3 conversion to C3b, C3a/C5a, platelet count, and white blood cell count (WBC) were also measured at the same time periods. No significant correlation existed between complement activation and hemodynamic events, as might have been evident by decreased CH50, increased C3 conversion to C3b, or elevations in C3a/C5a levels. PP significantly prevented the CO decrease occurring at 1 and 3 min following heparin reversal by protamine (-0.8 and -1.4 liters/min vs 0.1 and -0.2 liters/min, P P P = 0.06). These data support the conclusion that, contrary to earlier reports, adverse hemodynamic and hematologic responses accompanying protamine reversal of heparin anticoagulation do not appear to be correlated with activation of complement. In fact, those patients having the greatest C3a generation exhibited the least hemodynamic changes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29240/1/0000295.pd

Taxonomy based on science is necessary for global conservation

Peer reviewe

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Report on the present state of the Chesapeake and Ohio Canal : the estimated cost of completing it to Cumberland, and the prospects of income to be derived from the transportation upon it of the coal and iron of the mines in Alleghany County : with estimates of the comparative cost of transporting coal by the Canal, and by the Baltimore and Ohio Rail-Road : made at the request of Thomas W. Ward, Esq. ... /

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