A NEW ADAPTIVE WEIGHT ALGORITHM TO REMOVE SALT AND PEPPER NOISE FROM SATELLITE IMAGES

ABSTRACT In this paper, a new adaptive weight algorithm is developed for the removal of salt and pepper noise particularly in satellite images. Satellite images are corrupted when acquired by a defective sensor or when transmitted through a faulty channel. Salt and pepper noise can be commonly found in the sensor or transmission channel during acquisition and transmission of digital satellite images. This algorithm can be worked in two phases. During the first phase, detecting the noise pixel according to the correlations among image pixels and in second phase adaptive weight algorithm is used to remove the noise. Simulation results based on Matlab show that this method can eliminate the salt and pepper noise in satellite images efficiently and preserves edges and details information of the image. Also this method can remove noise for highly contaminated image with noise level as large as 90%, it still can get the better performance

Treatment of COVID-19 in pregnant women: A systematic review and meta-analysis

OBJECTIVE: Clinical trials evaluating pharmacological and non-pharmacological treatment of COVID-19, either excluded pregnant women or included very few women. Unlike the numerous systematic reviews on prevalence, symptoms and adverse outcomes of COVID-19 in pregnancy, there are very few on the effects of treatment on maternal and neonatal outcomes in pregnancy. We undertook a systematic review of all published and unpublished studies on the effects of pharmacological and non-pharmacological interventions for COVID-19 on maternal and neonatal pregnancy outcomes. DATA SOURCES: We performed a systematic literature search of the following databases: Medline, Embase, Cochrane database, WHO (World Health Organization) COVID-19 database, China National Knowledge Infrastructure (CNKI), and Wanfang databases from 1 December 2019 to 1 December 2020. STUDY ELIGIBILITY CRITERIA: Studies were only included if they involved pregnant or postnatal women who were exposed to pregnancy specific interventions like the mode of delivery and type of anaesthesia, pharmacological or non-pharmacological interventions. STUDY APPRAISAL AND SYNTHESIS METHODS: We first screened the titles and abstracts of studies and then assessed the full text of the selected studies in detail for eligibility. Data on study design, population, type of screening for COVID-19, country, hospital, country status (high or low and middle income), treatment given (mode of delivery, type of anaesthesia, type of pharmacological and non-pharmacological treatment was extracted. The pre-defined maternal outcomes we collected were mode of delivery (vaginal or by caesarean section), severe or critical COVID-19 (as defined by the authors), symptomatic COVID-19, maternal death, maternal hospital admission, ICU admission, mechanical ventilation, ECMO and maternal pneumonia. The pre-defined neonatal outcomes we extracted were preterm birth (<37 weeks), stillbirth, neonatal death, NICU admission, neonatal COVID-19 positive, neonatal acidosis (pH<7.0) and Apgar scores (<8 after 5 minutes). Study quality assessment was performed. RESULTS: From a total of 342 potential eligible studies, we included 27 studies in our systematic review, including 4943 pregnant women (appendix 3). Sixteen studies had a retrospective cohort design and 11 a prospective cohort design. There were no randomised controlled trials. There was a significant association between caesarean section and admission to ICU (OR 4.99, 95% CI 1.24 to 20.12; 4 studies, 153 women, I(2)=0%), and diagnosis of maternal COVID-19 pneumonia as defined by study authors (OR 3.09, 95% CI 1.52 to 6.28; 2 studies, 228 women, I(2)=0%). Women who had a preterm birth were more likely to have the baby via caesarean section (OR 3.03, 95% CI 1.71 to 5.36, 12 studies; 314 women, I(2)=0%). For pharmacological and non-pharmacological we provided estimates of the expected rates of outcomes in women exposed to various treatment of COVID-19. Comparative data for pregnant women, in particular for treatments proven to be effective in the general population, however, is lacking to provide clinically meaningful interpretation. CONCLUSIONS: We found associations for pregnancy specific interventions, like mode of delivery and outcomes of the disease, but there were too few data on pharmacological and non-pharmacological treatments in pregnant women with COVID-19. We report the rates of complications found in the literature. We encourage researchers to include pregnant women in their trials and report the data on pregnant women separately