Solution of linear equations and the inversion of matrices

Thesis (M.A.)--Boston UniversityIt has been noted that the writing of a system of linear equations in matrix form quite naturally suggests the computation of an inverse matrix which may then be used to compute solutions to a system of equations in which the coefficients remain the same but the constants have been changed. The elementary properties of matrices and determinants have been reviewed and a general method of matrix inversion based on these properties was considered. The very considerable practical deficiencies of this theoretically attractive method suggested that the method would be almost completely worthless for a system larger than two by two [TRUNCATED

Participation caught in-between projects and policies?

Over the recent decades, we have experienced a shift away from technocratic planning towards the idea of place-based mediation, and the role of society in making the city. Initiating new readings the role participation and collaboration has on: (a) consensus building between capacity of participants, (b) the encouraging of broad range of contexts to shape evidence-based decision-making, including sociocultural, economic, and technological contexts, and (c) new forms of partnerships and funding between academic, municipalities, and companies. This has lead to contemporary planning practice and theory embracing the idea of reimagining and redefining, complexities and contexts that shape the city. By carrying out a literature review, the discussion of new instruments, strategies and formats, and theories that are currently being employed is expanded on. The author questions if this has lead to an urbanism approach where the strategic and spatial, formal, and informal frameworks of participatory practices appear to coexist

Age and frailty are independently associated with increased COVID-19 mortality and increased care needs in survivors: results of an international multi-centre study

Introduction: Increased mortality has been demonstrated in older adults with coronavirus disease 2019 (COVID-19), but the effect of frailty has been unclear. Methods: This multi-centre cohort study involved patients aged 18 years and older hospitalised with COVID-19, using routinely collected data. We used Cox regression analysis to assess the impact of age, frailty and delirium on the risk of inpatient mortality, adjusting for sex, illness severity, inflammation and co-morbidities. We used ordinal logistic regression analysis to assess the impact of age, Clinical Frailty Scale (CFS) and delirium on risk of increased care requirements on discharge, adjusting for the same variables. Results: Data from 5,711 patients from 55 hospitals in 12 countries were included (median age 74, interquartile range [IQR] 54–83; 55.2% male). The risk of death increased independently with increasing age (>80 versus 18–49: hazard ratio [HR] 3.57, confidence interval [CI] 2.54–5.02), frailty (CFS 8 versus 1–3: HR 3.03, CI 2.29–4.00) inflammation, renal disease, cardiovascular disease and cancer, but not delirium. Age, frailty (CFS 7 versus 1–3: odds ratio 7.00, CI 5.27–9.32), delirium, dementia and mental health diagnoses were all associated with increased risk of higher care needs on discharge. The likelihood of adverse outcomes increased across all grades of CFS from 4 to 9. Conclusion: Age and frailty are independently associated with adverse outcomes in COVID-19. Risk of increased care needs was also increased in survivors of COVID-19 with frailty or older age.</p