1,350 research outputs found
Alaska Athabascan stellar astronomy
Thesis (M.A.) University of Alaska Fairbanks, 2014Stellar astronomy is a fundamental component of Alaska Athabascan cultures that facilitates time-reckoning, navigation, weather forecasting, and cosmology. Evidence from the linguistic record suggests that a group of stars corresponding to the Big Dipper is the only widely attested constellation across the Northern Athabascan languages. However, instruction from expert Athabascan consultants shows that the correlation of these names with the Big Dipper is only partial. In Alaska Gwich'in, Ahtna, and Upper Tanana languages the Big Dipper is identified as one part of a much larger circumpolar humanoid constellation that spans more than 133 degrees across the sky. The Big Dipper is identified as a tail, while the other remaining asterisms within the humanoid constellation are named using other body part terms. The concept of a whole-sky humanoid constellation provides a single unifying system for mapping the night sky, and the reliance on body-part metaphors renders the system highly mnemonic. By recognizing one part of the constellation the stargazer is immediately able to identify the remaining parts based on an existing mental map of the human body. The circumpolar position of a whole-sky constellation yields a highly functional system that facilitates both navigation and time-reckoning in the subarctic. Northern Athabascan astronomy is not only much richer than previously described; it also provides evidence for a completely novel and previously undocumented way of conceptualizing the sky--one that is unique to the subarctic and uniquely adapted to northern cultures. The concept of a large humanoid constellation may be widespread across the entire subarctic and have great antiquity. In addition, the use of cognate body part terms describing asterisms within humanoid constellations is similarly found in Navajo, suggesting a common ancestor from which Northern and Southern Athabascan stellar naming strategies derived.Chapter 1: Introductory materials -- 1.1. Introduction -- 1.2. Literature review -- 1.2.1 Southern Athabascan sources -- 1.2.2 Alaska Athabascan sources -- 1.2.3 Canadian Athabascan sources -- 1.2.4 Alaska Athabascan dictionaries -- 1.2.5 Unpublished materials -- 1.3 Methodology -- 1.4 The Athabascan language family -- Chapter 2: The Athabascan starscape: Whole-sky constellations -- 2.1 Gwich'in Yahdii -- 2.2 Upper Tanana Yihdaa and Neek'e'eltiin -- 2.3 Ahtna Nek'e Neghaltaexi and Nek'eltaeni -- 2.4 Dena'ina Naq'eltani and Yuq'eltaeni -- 2.5 Koyukon Naagheltaale -- 2.6 Tanacross Neek'e'elteen -- 2.7 Fragmentary evidence from the other Alaska Athabascan languages -- 2.8 Chapter two conclusion -- Chapter 3: Linguistic evidence for a pan-Athabascan strategy for mapping the sky -- 3.1 Two widely attested Athabascan forms for the Big Dipper -- 3.1.1 Category A: Yahdii and cognates thereof -- 3.1.2 Category B: Big Dipper terms that share common verb stems and prefix morphenes -- 3.1.3 Category C: Other Big Dipper terms -- 3.3 Body part asterisms -- 3.4 Chapter three conclusion -- Chapter 4: The function and utility of Alaska Athabascan stellar astronomy -- 4.1 Stellar time-reckoning -- 4.1.1 A Tripartite stellar time-reckoning system -- 4.1.2 The Big Dipper and whole-sky constellations in time-reckoning -- 4.1.3 The morning stars in time-reckoning -- 4.1.4 The Sun in time-reckoning -- 4.2 Stellar orientation -- 4.2.1 Stellar orientation: A basic strategy -- 4.2.3 Stellar orientation: A complex strategy -- 4.3 Weather signs Interpreted from the stars -- 4.4 Stars in cosmology and religion -- 4.4.1 The creation or placement of the stars -- 4.4.2 Taboos, protocols, and other stellar beliefs -- 4.4.3 Humanoid constellations in Athabascan belief systems -- 4.5 Chapter four conclusion -- Conclusion -- References -- Appendices
Overcoming thrombolytic resistance Rationale and initial clinical experience combining thrombolytic therapy and glycoprotein IIb/IIIa receptor inhibition for acute myocardial infarction
AbstractOBJECTIVESWe sought to review the emerging data and the clinical rationale for combining glycoprotein (GP) IIb/IIIa inhibitors with thrombolytic therapy for acute myocardial infarction (AMI).BACKGROUNDAlthough thrombolytic therapy has been a major advance in the treatment of acute ST segment elevation MI, new single-bolus thrombolytic agents have been unable to break the “thrombolytic ceiling” in infarct-related artery (IRA) patency.METHODSRecent literature on GPIIb/IIIa inhibitors in acute coronary syndromes was reviewed.RESULTSA new approach toward improving current thrombolytic–antithrombotic regimens focuses on “targeted therapy” for each component of the occlusive coronary thrombus: fibrin, thrombin and platelets. For the fibrin component, front-loading and/or bolus dosing of plasminogen activators (PAs) has identified the currently available doses of tissue-type plasminogen activator (t-PA) and recombinant tissue-type plasminogen activator (r-PA). For the thrombin component, several recent trials have shown that lower doses of heparin improve the safety profile of the thrombolytic-antithrombotic regimen. For the platelet component, aspirin has been shown to be effective, but the GPIIb/IIIa inhibitors offer the potential for more effective platelet inhibition and improved clinical efficacy. The benefits of GPIIb/IIIa inhibition in reducing death, MI or urgent revascularization in the setting of percutaneous coronary intervention are well established. Emerging experimental and clinical data now suggest that combining GPIIb/IIIa inhibition with reduced-dose thrombolytic therapy may improve early IRA patency without increasing bleeding risk.CONCLUSIONSGiven the strong clinical and physiologic rationale, clinical investigation in acute ST segment elevation MI is currently focused on combining the potent GPIIb/IIIa receptor inhibitors with reduced-dose fibrinolytic agents in acute MI, with the goal of overcoming “thrombolytic resistance.
Unmanned tactical autonomous control and collaboration coactive design
Unmanned tactical autonomous control and collaboration (UTACC) is a Marine Corps experimental research initiative with the overarching aim of developing a collaborative human-robotic system of systems (SoS). This thesis analyzed the results of the existing UTACC concept development and incorporated them into an emergent human-robotic system development method, Coactive Design. An advantage to using this method is that it includes the human and his or her internal processes when modeling the system. As such, the focus is shifted to supplementing team capacities vice developing autonomy. The two aims of this thesis are (1) to provide a recommendation for incorporating the Coactive Design method into the systems' development life cycle and (2) to provide a list of design requirements for a resilient UTACC SoS. Resilience is realized by designing for flexibility. A teamwork infrastructure built on many interdependent relationships provides this flexibility. These interdependent relationships can be grouped into three areas: observability, predictability, and directability. Counter to conventional practices within the robotics industry, Coactive Design focuses on managing these interdependencies rather than focusing on autonomy. Coactive Design also provides a cost-benefit analysis of development choices, which assists with developing efficiencies during the design and development of the system.http://archive.org/details/unmannedtactical1094549417Outstanding ThesisCaptain, United States Marine CorpsApproved for public release; distribution is unlimited
Cost estimation of post production software support in ground combat systems
Weapon systems and programs are becoming increasingly more dependent on software as a critical technology for the success of the programs. Along with this dependence on performance, the costs associated with software are becoming an increasing share of the life cycle costs of these weapon systems and programs. Life cycle software costs are divided into two phases, development and maintenance. There are numerous popular models to aid developers and independent estimators in predicting costs and schedules for software development. Some of these models are open source, many others are proprietary. These models are based on research performed on existing software systems and historical data. However, for software maintenance, there are far fewer models, research efforts, or collected data sets. The Army's term for software maintenance is post production software support. This thesis describes how this support is currently funded, performed, and estimated. The model presented could be adopted to manage support of Army ground combat systems. This thesis is furthers the understanding of the software maintenance support costs associated with weapon systems. In addition to specific results on ground combat systems presented, the thesis provides insight into maintaining other large software-dependent systems and recommendations on further research in the field.http://archive.org/details/costestimationof109453352US Marine Corps (USMC) author.Approved for public release; distribution is unlimited
Teacher and Student Perceptions of Computer-Assisted Instructional Software to Differentiate Instruction
Many educators struggle to meet the academic needs of students, especially in the subject area of mathematics. Computer-assisted instruction is an instructional strategy used to enhance instruction. However, there is limited research on the effectiveness of these software programs for all students. The purpose of this qualitative, embedded, multiple case study was to explore the perceptions of teachers and students using computer-assisted instructional software to differentiate instruction within a general education and special education 4th-grade mathematics classroom. The constructivism theory provided a framework for the topic of differentiated instruction. This study included a single elementary school within a district in the Southeastern United States. The participants of this study included 1 general education and 1 special education 4th-grade mathematics teacher. In addition, participants included 6 general education and 4 special education 4th-grade mathematics students. Introductory and follow-up teacher interviews, introductory and follow-up student focus group interviews, 6 classroom observations, and teacher lesson plans were used as data collection methods. Gerund coding, categorizing, and content analysis was employed to interrogate the data. The constant comparative method was used to determine within-case and across-case themes and discrepancies. The findings revealed that teachers used computer-assisted instructional software, MobyMax, to meet individual student needs, monitor student progress, implement small group instruction, increase student engagement, and supplement primary teacher-led instruction. Educators can use the findings of this study to understand how teachers can use computer-assisted instruction to meet the needs of students
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Anticoagulation in patients with atrial fibrillation and heart failure: Insights from the NCDR PINNACLE-AF registry.
BackgroundIn non-valvular atrial fibrillation (NVAF) patients, congestive heart failure (CHF) confers an increased risk of stroke or systemic thromboembolism. This risk is present in both heart failure (HF) with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). It is unclear if clinicians account for both types of CHF in their NVAF anticoagulation practices. Accordingly, we characterized current outpatient anticoagulation trends in NVAF patients with HFpEF compared to patients with HFrEF.MethodsThe outpatient NCDR PINNACLE-AF registry was analyzed to identify patients with NVAF and CHF. The study population was subdivided into HFpEF (ie, LVEF ≥ 40%) and HFrEF (LVEF < 40%). Anticoagulation rates by CHF group were compared and stratified by CHA2 DS2 -VASc score.ResultsA total of 340 127 patients with NVAF and CHF were identified, of whom 248 136 (73.0%) were classified as HFpEF and 91 991 (27.0%) as HFrEF. Patients with HFpEF had higher mean CHA2 DS2 -VASc scores and were more likely to be female, older, and have hypertension (P < 0.001). Unadjusted anticoagulation rates were significantly lower in patients with HFpEF compared to those with HFrEF (60.6% vs 64.2%, respectively). Lower rates of anticoagulation in the HFpEF group persisted after risk adjustment (RR: 0.93 [95% CI: 0.91, 0.94]). Stratification by CHA2 DS2 -VASc score demonstrated that lower rates of anticoagulation in patients with HFpEF persisted until a score of ≥5.ConclusionsPatients with NVAF and HFpEF have significantly lower anticoagulation rates when compared to their HFrEF counterparts. These findings suggest a potential underappreciation of HFpEF as a risk factor in patients with NVAF
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PCSK9 inhibitor valuation: A science‐based review of the two recent models
Low‐density lipoprotein cholesterol (LDL‐C) has been extensively evaluated. Prospective cohort studies, randomized controlled trials, biology, pathophysiology, genetics, and Mendelian randomization studies, have clearly taught us that LDL‐C causes atherosclerotic cardiovascular disease. The newest class of drugs to lower LDL‐C, the proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies, have been found to safely reduce LDL‐C approximately 60% when added to high‐intensity statin therapy. Because their cost is much greater than that of the currently available agents, their value has been questioned. In late August, 2017, two groups assessed the value of this class of drugs looking at cost‐effectiveness; however, the Institute for Clinical and Economic Review and Fonarow and colleagues found disparate results when assessing PCSK9 valuation. Herein, we review the evolution of LDL‐C from hypothesis to fact, and then attempt to adjudicate the 2 models, shedding light on the complex modeling process. We find that models of cost‐effectiveness are helpful adjuncts to decision making, but that their conclusions depend on many assumptions. Ultimately, clinician judgment regarding their clinical benefit, balanced by some estimation of cost, may be more productive to target the right patients for whom the benefits can be well‐justified
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