Inference for Step-Stress Partially Accelerated Life Test Model with an Adaptive Type-I Progressively Hybrid Censored Data

Consider estimating data of failure times under step-stress partially accelerated life tests based on adaptive Type-I hybrid censoring. The mathematical model related to the lifetime of the test units is assumed to follow Rayleigh distribution. The point and interval maximum-likelihood estimations are obtained for distribution parameter and tampering coefficient. Also, the work is conducted under a traditional Type-I hybrid censoring plan (scheme). A Monte Carlo simulation algorithm is used to evaluate and compare the performances of the estimators of the tempering coefficient and model parameters under both progressively hybrid censoring plans. The comparison is carried out on the basis of mean squared errors and bias

Comparison of HRCT of chest findings in different waves during the COVID-19 pandemic: a retrospective descriptive study in COVID dedicated hospital in Bangladesh

Background: The existing COVID-19 epidemic has affected masses of people universally, leading to significant morbidity and mortality. Radiological imaging methods such as high-resolution computed tomography (HRCT), computed tomography (CT) and chest x-ray have played an essential role in diagnosing and managing COVID-19. Methods: This cross-sectional and observational study was conducted in the department of radiology and imaging, Kurmitola General Hospital, Dhaka, Bangladesh, a COVID dedicated hospital. A total number of 469 patients (N=469) from ≤20 to ≥90 years old were included in the study. Data analysis was performed using Statistical Package for the Social Sciences (SPSS) version 25.0. Results: Based on distribution by age group, the highest number of cases in all three waves were among individuals aged 51-60 (126, 26.9%), followed by those aged 61-70 (97, 20.7%) and 41-50 (90, 19.2%). Among the patients with subtle GGO, the proportion of cases was highest in the first wave, followed by a decrease in the second wave and a further decrease in the third wave. The proportion of patients with SCL was highest in the second (44.9%) wave and decreased in the third (5.9%) wave. For both LUL and LLL, the majority of cases with radiological were observed in the “yes” group in all waves, with significantly higher proportions in the “yes” group compared to the “no” group (p value <0.001). Conclusions: The findings highlighted the significance of incorporating routine radiological examinations and monitoring of radiological features in managing and treating COVID-19 patients. The findings in the study also suggested that the percentage of lung involvement increased from the first to the third wave of COVID-19, which is consistent with the increasing trend of COVID-19 cases during the same period

Statistical Inference for Burr Type X Distribution using Geometric Process in Accelerated Life Testing Design for Time censored data

In accelerated life testing researcher generally use a life stress relationship between life characteristic and stress to estimate the parameters of failure time distributions at use condition which is just a re-parameterization of original parameters but from statistical point of view it is easy and reasonable to deal with original parameters of the distribution directly instead of developing inference for the parameters of the life stress relationship. So, an attempt is made here to estimate the parameters of Burr Type X life distribution directly in accelerated life testing by assuming that the lifetimes at increasing stress levels forms a geometric process. A mathematical model for the analysis of constant stress accelerated life testing for type-I censored data is developed and the estimates of parameters are obtained by using the maximum likelihood method. Also a Fisher information matrix is constructed in order to get the asymptotic variance and interval estimates of the parameters. Lastly, a simulation study is performed to illustrate the statistical properties of the parameters and the confidence intervals

Bayesian Analysis and Reliability Estimation of Generalized Probability Distributions

This edited volume entitled “Bayesian Estimation and Reliability Estimation of Generalized Probability Distributions” is being published for the benefit of researchers and academicians. It contains ten different chapters covering a wide range of topics both in applied mathematics and statistics. The proofs of various theorems and examples have been given with minute details. During the preparation of the manuscript of this book, the editor has incorporated the fruitful academic suggestions provided by Dr. Peer Bilal Ahmad, Dr. Sheikh Parvaiz Ahmad, Dr. J. A. Reshi, Dr. Tanveer Ahmad Tarray, Dr. Kowsar Fatima, Dr. Ahmadur Rahman, Dr. Showkat Ahmad Lone, Mudasir Sofi, Uzma Jan, Aaliya Syed, and Dr. Humaira Sultan. It is expected to have good popularity due to its usefulness among its readers and users

Pralsetinib in patients with RET fusion-positive non-small cell lung cancer: A plain language summary of the ARROW study

What is this summary about?This is a summary of a research study called ARROW, which tested a medicine called pralsetinib in patients with non-small cell lung cancer (NSCLC), thyroid cancer, and other advanced solid tumours caused by a change in a gene called RET. For the purposes of this summary, only patients with NSCLC with a change in RET called fusion (RET fusion+) are highlighted.What were the results?In total, 281 patients with RET fusion+ NSCLC had taken part in this study across the USA, Europe, and Asia. Patients were asked to take four pills (adding up to 400 mg) of pralsetinib each day and were checked for any changes in their tumours, as well as for any side effects. After an average of 8 months of treatment with pralsetinib, 72% of previously untreated patients and 59% of patients who had previously received chemotherapy had considerable shrinkage of their tumours. Among 10 patients with tumours which had spread to the brain (all of whom had received previous treatments), 70% had their tumours shrink greatly in the brain after treatment with pralsetinib.On average, patients lived with little to no tumour growth for 16 months. In previously untreated patients, the most common severe side effects that were considered related to pralsetinib treatment were decreased white blood cells (neutrophils and lymphocytes), increased blood pressure, and an increase in a blood protein called creatine phosphokinase. In previously treated patients, the severe side effects were decreased white blood cells (neutrophils, lymphocytes, and leukocytes), increased blood pressure, and low levels of red blood cells. In both untreated and previously treated patients, the most common severe side effects that required hospital attention were lung inflammation/swelling causing shortness of breath (pneumonitis) and lung infection (pneumonia).What were the results? In total, 281 patients with RET fusion+ NSCLC had taken part in this study across the USA, Europe, and Asia. Patients were asked to take four pills (adding up to 400 mg) of pralsetinib each day and were checked for any changes in their tumours, as well as for any side effects. After an average of 8 months of treatment with pralsetinib, 72% of previously untreated patients and 59% of patients who had previously received chemotherapy had considerable shrinkage of their tumours. Among 10 patients with tumours which had spread to the brain (all of whom had received previous treatments), 70% had their tumours shrink greatly in the brain after treatment with pralsetinib. On average, patients lived with little to no tumour growth for 16 months. In previously untreated patients, the most common severe side effects that were considered related to pralsetinib treatment were decreased white blood cells (neutrophils and lymphocytes), increased blood pressure, and an increase in a blood protein called creatine phosphokinase. In previously treated patients, the severe side effects were decreased white blood cells (neutrophils, lymphocytes, and leukocytes), increased blood pressure, and low levels of red blood cells. In both untreated and previously treated patients, the most common severe side effects that required hospital attention were lung inflammation/swelling causing shortness of breath (pneumonitis) and lung infection (pneumonia).What do the results mean?Overall, the ARROW study showed that pralsetinib was effective in shrinking tumours in patients with RET fusion+ NSCLC regardless of previous treatment history. The recorded side effects were expected in patients receiving this type of medicine. Clinical Trial Registration: NCT03037385 (ARROW) (ClinicalTrials.gov)Y