87 research outputs found

    The dynamics of tethers and space-webs

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    The thesis 'The dynamics of tethers and space-webs' investigates the motion of the Motorized Momentum Exchange Tether (MMET) on an inclined orbit, and while deploying and retracting symmetric payloads. The MMET system is used as a basis for examining the stability of space-webs using a triangular structure of tethers while rotating. The motion of small robots is introduced as they move on the space-web, and their motions are found to influence the behaviour of the structure. Several methods of limiting the destabilising influences of the robots are considered, and are found to stabilise the web in most circumstances. A structured method for describing the rotations of a tether system is outlined, and different rotational systems are compared. This lays the foundation for the further chapters examining MMET dynamics on an inclined orbit and while deploying and recovering the payloads. Lagrange's equations are generated for the three cases, and are solved using standard numerical integration techniques. To emphasise the practical uses of the MMET system, several missions are analysed by using the system as a re-usable launcher for micro-satellite payloads.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Correspondence between practitioners’ self-assessment and independent motivational interviewing treatment integrity ratings

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    As evaluation of practitioners’ competence is largely based on self-report, accuracy in practitioners’ self-assessment is essential for ensuring high quality treatment-delivery. The aim of this study was to assess the relationship between independent observers’ ratings and practitioners’ self-reported treatment integrity ratings of Motivational interviewing (MI). Practitioners (N = 134) were randomized to two types of supervision [i.e., regular institutional group supervision, or individual telephone supervision based on the MI Treatment Integrity (MITI) code]. The mean age was 43.2 years (SD = 10.2), and 62.7 percent were females. All sessions were recorded and evaluated with the MITI, and the MI skills were self-assessed with a questionnaire over a period of 12 months. The associations between self-reported and objectively assessed MI skills were overall weak, but increased slightly from baseline to the 12-months assessment. However, the self-ratings from the group that received monthly objective feedback were not more accurate than those participating in regular group supervision. These results expand findings from previous studies and have important implications for assessment of practitioners’ treatment fidelity: Practitioners may learn to improve the accuracy of self-assessment of competence, but to ensure that patients receive intended care, adherence and competence should be assessed objectively

    2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the Diagnosis and Management of Patients With Thoracic Aortic Disease: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine

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    The writing committee conducted a comprehensive search of the medical and scientific literature through the use of PubMed/MEDLINE. Searches were limited to publications written in the English language. Compiled reports were reviewed and additional articles were provided by committee members. Specifically targeted searches were conducted on the following subtopics: acute aortic dissection, ankylosing spondylitis, aortic dissection and litigation, aortic neoplasm, aortic tumors, Behçet disease, bicuspid aortic valve, calcified aorta, chronic dissection, coarctation of the aorta, D-dimer, dissecting aneurysm, Ehlers-Danlos syndrome, endovascular and aortic aneurysms, medial degeneration, porcelain aorta, giant cell arteritis, imaging and thoracic aortic disease, inflammatory disease, intramural hematoma, Loeys-Dietz syndrome, Marfan syndrome, Noonan syndrome, penetrating aortic ulcer, polycystic kidney disease, thoracic and aortic aneurysms, thoracic aortic disease and patient care, thoracic aortic disease and surgery, thoracic aorta and Kawasaki disease, Takayasu arteritis, thoracoabdominal and aorta or aortic disease, and Turner syndrome. More than 850 references were reviewed, with 830 used as the primary evidence base for the final guideline. The ACCF/AHA Task Force on Practice Guidelines methodology processes were followed to write the text and recommendations. In general, published manuscripts appearing in journals listed in Index Medicus were used as the evidence base. Published abstracts were used only for emerging information but were not used in the formulation of recommendations
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