Optimal fuzzy proportional-integral-derivative control for a class of fourth-order nonlinear systems using imperialist competitive algorithms

The proportional integral derivative (PID) controller has gained wide acceptance and use as the most useful control approach in the industry. However, the PID controller lacks robustness to uncertainties and stability under disturbances. To address this problem, this paper proposes an optimal fuzzy-PID technique for a two-degree-of-freedom cart-pole system. Fuzzy rules can be combined with controllers such as PID to tune their coefficients and allow the controller to deliver substantially improved performance. To achieve this, the fuzzy logic method is applied in conjunction with the PID approach to provide essential control inputs and improve the control algorithm efficiency. The achieved control gains are then optimized via the imperialist competitive algorithm. Consequently, the objective function for the cart-pole system is regarded as the summation of the displacement error of the cart, the angular error of the pole, and the control force. This control concept has been tested via simulation and experimental validations. Obtained results are presented to confirm the accuracy and efficiency of the suggested method. © 2022 S. Hadipour Lakmesari et al

An ethnographic investigation of maternity healthcare experience of immigrants in rural and urban Alberta, Canada

Background: Canada is among the top immigrant-receiving nations in the world. Immigrant populations may face structural and individual barriers in the access to and navigation of healthcare services in a new country. The aims of the study were to (1) generate new understanding of the processes that perpetuate immigrant disadvantages in maternity healthcare, and (2) devise potential interventions that might improve maternity experiences and outcomes for immigrant women in Canada. Methods: The study utilized a qualitative research approach that focused on ethnographic research design and data analysis contextualized within theories of organizational behaviour and critical realism. Data were collected over 2.5 years using focus groups and in-depth semistructured interviews with immigrant women (n = 34), healthcare providers (n = 29), and social service providers (n = 23) in a Canadian province. Purposive samples of each subgroup were generated, and recruitment and data collection – including interpretation and verification of translations – were facilitated through the hiring of community researchers and collaborations with key informants. Results: The findings indicate that (a) communication difficulties, (b) lack of information, (c) lack of social support (isolation), (d) cultural beliefs, e) inadequate healthcare services, and (f) cost of medicine/services represent potential barriers to the access to and navigation of maternity services by immigrant women in Canada. Having successfully accessed and navigated services, immigrant women often face additional challenges that influence their level of satisfaction and quality of care, such as lack of understanding of the informed consent process, lack of regard by professionals for confidential patient information, short consultation times, short hospital stays, perceived discrimination/stereotyping, and culture shock. Conclusions: Although health service organizations and policies strive for universality and equality in service provision, personal and organizational barriers can limit care access, adequacy, and acceptability for immigrant women. A holistic healthcare approach must include health informational packages available in different languages/media. Health care professionals who care for diverse populations must be provided with training in cultural competence, and monitoring and evaluation programs to ameliorate personal and systemic discrimination

The use of oral glucocorticoids and the risk of major osteoporotic fracture in patients with myasthenia gravis

SUMMARY: Oral glucocorticoids may increase major osteoporotic fracture risk (MOF) in myasthenia gravis patients. To assess this risk, we performed a case–control study including all Danish patients with a MOF between 1995 and 2011. We also pooled our data with data from another study. We found no increased risk. Osteoporosis prevention remains advisable. PURPOSE/INTRODUCTION: The prolonged use of high doses of oral glucocorticoids (GCs), a common treatment in patients with myasthenia gravis (MG), may increase major osteoporotic fracture (MOF) risk. Previous epidemiological studies did not exclusively focus on patients with MG or had relatively few GC-exposed MG patients. Aims were to evaluate the risk of MOF in MG patients using oral GCs in a large study population and to perform a pooled analysis with data from previous work. METHODS: A population-based case–control study (1995–2011) was conducted using the Danish National Health Service. Cases had sustained a MOF, and controls had not. All were aged ≥ 18 years. Multivariate conditional logistic regression estimated odds ratios (ORs) among MG patients using oral GCs versus non-users. Adjustments were made for comorbidities and comedications. In the pooled analysis, results were pooled by the use of generic inverse variance methods, assuming a random-effects model. RESULTS: We identified 376,858 cases and 376,858 controls. MOF risk was not elevated in MG patients currently using oral GCs compared to MG patients not on oral GCs (OR(adj.): 1.26 (95% CI 0.68–2.33)). The use of the highest cumulative dose of oral GCs (≥ 7 g) did not show an increased risk of MOF among MG patients (OR(adj.): 2.00 (95% CI 0.90–4.44)). Our pooled analysis also showed no association between oral GC use and MOF risk. CONCLUSION: This study showed that oral GC use in patients with MG was not associated with increased risk of MOF in our case–control study and pooled analysis. Osteoporosis prevention in MG patients based on clinical guidelines remains advisable

Association between Clinical Frailty Scale score and hospital mortality in adult patients with COVID-19 (COMET): an international, multicentre, retrospective, observational cohort study

Background: During the COVID-19 pandemic, the scarcity of resources has necessitated triage of critical care for patients with the disease. In patients aged 65 years and older, triage decisions are regularly based on degree of frailty measured by the Clinical Frailty Scale (CFS). However, the CFS could also be useful in patients younger than 65 years. We aimed to examine the association between CFS score and hospital mortality and between CFS score and admission to intensive care in adult patients of all ages with COVID-19 across Europe. Methods: This analysis was part of the COVID Medication (COMET) study, an international, multicentre, retrospective observational cohort study in 63 hospitals in 11 countries in Europe. Eligible patients were aged 18 years and older, had been admitted to hospital, and either tested positive by PCR for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or were judged to have a high clinical likelihood of having SARS-CoV-2 infection by the local COVID-19 expert team. CFS was used to assess level of frailty: fit (CFS1–3), mildly frail (CFS4–5), or frail (CFS6–9). The primary outcome was hospital mortality. The secondary outcome was admission to intensive care. Data were analysed using a multivariable binary logistic regression model adjusted for covariates (age, sex, number of drugs prescribed, and type of drug class as a proxy for comorbidities). Findings: Between March 30 and July 15, 2020, 2434 patients (median age 68 years [IQR 55–77]; 1480 [61%] men, 954 [30%] women) had CFS scores available and were included in the analyses. In the total sample and in patients aged 65 years and older, frail patients and mildly frail patients had a significantly higher risk of hospital mortality than fit patients (total sample: CFS6–9 vs CFS1–3 odds ratio [OR] 2·71 [95% CI 2·04–3·60], p<0·0001 and CFS4–5 vs CFS1–3 OR 1·54 [1·16–2·06], p=0·0030; age ≥65 years: CFS6–9 vs CFS1–3 OR 2·90 [2·12–3·97], p<0·0001 and CFS4–5 vs CFS1–3 OR 1·64 [1·20–2·25], p=0·0020). In patients younger than 65 years, an increased hospital mortality risk was only observed in frail patients (CFS6–9 vs CFS1–3 OR 2·22 [1·08–4·57], p=0·030; CFS4–5 vs CFS1–3 OR 1·08 [0·48–2·39], p=0·86). Frail patients had a higher incidence of admission to intensive care than fit patients (CFS6–9 vs CFS1–3 OR 1·54 [1·21–1·97], p=0·0010), whereas mildly frail patients had a lower incidence than fit patients (CFS4–5 vs CFS1–3 OR 0·71 [0·55–0·92], p=0·0090). Among patients younger than 65 years, frail patients had an increased incidence of admission to intensive care (CFS6–9 vs CFS1–3 OR 2·96 [1·98–4·43], p<0·0001), whereas mildly frail patients had no significant difference in incidence compared with fit patients (CFS4–5 vs CFS1–3 OR 0·93 [0·63–1·38], p=0·72). Among patients aged 65 years and older, frail patients had no significant difference in the incidence of admission to intensive care compared with fit patients (CFS6–9 vs CFS1–3 OR 1·27 [0·92–1·75], p=0·14), whereas mildly frail patients had a lower incidence than fit patients (CFS4–5 vs CFS1–3 OR 0·66 [0·47–0·93], p=0·018). Interpretation: The results of this study suggest that CFS score is a suitable risk marker for hospital mortality in adult patients with COVID-19. However, treatment decisions based on the CFS in patients younger than 65 years should be made with caution. Funding: LOEY Foundation