Safe Reinforcement Learning using Data-Driven Predictive Control

Reinforcement learning (RL) algorithms can achieve state-of-the-art performance in decision-making and continuous control tasks. However, applying RL algorithms on safety-critical systems still needs to be well justified due to the exploration nature of many RL algorithms, especially when the model of the robot and the environment are unknown. To address this challenge, we propose a data-driven safety layer that acts as a filter for unsafe actions. The safety layer uses a data-driven predictive controller to enforce safety guarantees for RL policies during training and after deployment. The RL agent proposes an action that is verified by computing the data-driven reachability analysis. If there is an intersection between the reachable set of the robot using the proposed action, we call the data-driven predictive controller to find the closest safe action to the proposed unsafe action. The safety layer penalizes the RL agent if the proposed action is unsafe and replaces it with the closest safe one. In the simulation, we show that our method outperforms state-of-the-art safe RL methods on the robotics navigation problem for a Turtlebot 3 in Gazebo and a quadrotor in Unreal Engine 4 (UE4)

Antifungal Activity of Green and Chemically Synthesized ZnO Nanoparticles against Alternaria citri, the Causal Agent Citrus Black Rot

Citrus black rot is a serious disease of citrus plants caused by Alternaria citri. The current study aimed to synthesize zinc oxide nanoparticles (ZnO-NPs) by chemically or green method and investigate their anti -fungal activity against A. citri. The sizes of synthesized as measured by transmission electron microscope of ZnO-NPs were 88 and 65 nm for chemical and green methods, respectively. The studied prepared ZnO-NPs were applied, in vitro and in situ, at different concen-trations (500, 1,000, and 2,000 & mu;g/ml) in post-harvest treatment on navel orange fruits to verify the possible control effect against A. citri. Results of in vitro assay demonstrated that, at concentration 2,000 & mu;g/ml, the green ZnO-NPs was able to inhibit about 61% of the fungal growth followed by 52% of chemical ZnO-NPs. In addition, scanning electron microscopy of A. citri treated in vitro with green ZnO-NPs showed swelling and deformation of conidia. Results showed also that, using a chemically and green ZnO-NPs at 2,000 & mu;g/ml in situ in post-harvest treatment of orange, artificially -infected with A. citri, has reduced the disease severity to 6.92% and 9.23%, respectively, compared to 23.84% of positive control (non-treated fruits) after 20 days of storage. The out findings of this study may contribute to the development of a natural, effective, and eco-friendly strategy for eradicating harmful phytopatho-genic fungi

Effect of tranexamic acid in prevention of postpartum hemorrhage in elective caesarean delivery: a randomized controlled study

Background: Postpartum hemorrhage is the ugly ghost that most obstetricians believe because many cases unpredicted and may be associated with rapid patient deterioration that may lead mortality or developing serious long-term morbidities. The objective of this study is to assess the efficacy of slowly intravenous administration of tranexamic acid in prevention and decline the severity of postpartum hemorrhage immediately prior to elective caesarean section.Methods: A double blinded, randomized, case control trial carried out at Obstetrics and Gynecology Department, Faculty of Medicine, South Valley University, Egypt from May 2017 to April 2018. This study was conducted on 500 full term pregnant women underwent elective caesarean section. The patients were divided randomly into: Group A (study group) included 250 patients received tranexamic acid 1gm slowly iv over 2 minutes at least 10 minutes before operation started and Group B (control group) included 250 patients that received placebo (normal saline NaCl 0.9%).Results: Incidence of PPH in group A and group B were (4.4% and 6.8) respectively, 1.2% in group A and 2.8% in group B had severe degree of PPH. Amount of blood loss immediately after placental delivery up to first 6 hours postoperative was statistically significant increase in placebo group than tranexamic acid group with p value <0.001.Conclusions: Tranexamic acid administration few minutes prior to elective cesarean section was effective in reducing the incidence and severity of PPH and decreased the use of additional uterotonic drugs and additional surgical interventions

Maternal satisfaction with delivery services at tertiary university hospital in upper Egypt, is it actually satisfying?

Background: Maternal health has therefore become an important aspect of policy and planning for healthcare, as reflected by its inclusion as the fifth Millennium Development Goal (MDG). The objective of the present investigation was to determine the maternal satisfaction towards delivery services at Women's Health Hospital, Assiut University, Upper EgyptMethods: A cross sectional study was performed. The study was conducted during February- April 2016 on a sample of 400 delivering mothers; the data were collected using a semi-structured questionnaire and analyzed by SPSS version21. Statistical tests were used, and significance level was taken at p-value <0.05.Results: A total of 400 delivering mothers were interviewed, of which 67.0 % of the respondents were between the age group of 20-30, 76.75 % were from rural areas, 48.0%were illiterate, 86.75% were house wives and 46.0% belonged to the income group of less than 500 EGP. The findings of the study showed that the overall maternal satisfaction level with the delivery services rendered at the hospital was 78.5%, while 21.5% were dissatisfied. Furthermore, satisfaction with the delivery service was found to have a significant association with the age of the respondents and educational level of the respondents. Moreover, results suggest that women are satisfied with the communication factors, interpersonal behavior, good management, and general satisfaction. Women were least satisfied with privacy sensation during hospital stay and obligatory blood donation.Conclusions: Although most participants were satisfied by the delivery service provided to them during delivery, Dissatisfaction by a minority group resulted in a limited ability of communication with mothers, lack of privacy sensation during hospital stay and obligatory blood donation. Thus, mechanisms should be developed to increase maternal satisfaction in our hospital

Influence of immediate postpartum contraception counseling on the rate of unintended pregnancy in primigravida: a randomized controlled study

Background: The current study aims to assess the influence of immediate postpartum counselling about effective contraceptive methods to be used by primigravida on the rate of unintended pregnancy during first 6 months post-partum.Methods: The study was a prospective randomized controlled trial for assessment the influence of immediate postpartum counseling about effective contraceptive methods to be used by primigravida on the rate of unintended pregnancy during first 6 months post-partum who delivered at the period between the 1st of December 2016 and 31st of December 2017. The study patients were randomly assigned into two groups: Group (A) were received counseling about contraceptive methods using illustrations through postpartum interview with the study researcher. Group (B) were not received any counseling about contraceptive methods. The primary outcome was the difference in the rate of unintended pregnancy in both groups.Results: No significant difference between both groups in preventing unintended pregnancy. In group (A): After 3 months postpartum 140 women (93.3%) were used the contraceptive method correctly. 10 women used method incorrectly and 2 of them get pregnant. After 6 months postpartum 8 women did not use any method but 134 women (95.7%) were correctly used the contraceptive method. In group (B): After 3 months postpartum 127 women (84.7%) were used the contraceptive method correctly. 23 women used method incorrectly and 4 of them get pregnant. After 6 months postpartum 1 woman did not use any method but 30 women (20.7%) were incorrectly used the contraceptive method.Conclusions: Immediate post-partum counseling about contraceptive methods is good tool to educate women who intend to have optimal inter–pregnancy period about the effective methods that suit them and when to initiate

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10&nbsp;years; 78.2% included were male with a median age of 37&nbsp;years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Breast cancer management pathways during the COVID-19 pandemic: outcomes from the UK ‘Alert Level 4’ phase of the B-MaP-C study

Abstract: Background: The B-MaP-C study aimed to determine alterations to breast cancer (BC) management during the peak transmission period of the UK COVID-19 pandemic and the potential impact of these treatment decisions. Methods: This was a national cohort study of patients with early BC undergoing multidisciplinary team (MDT)-guided treatment recommendations during the pandemic, designated ‘standard’ or ‘COVID-altered’, in the preoperative, operative and post-operative setting. Findings: Of 3776 patients (from 64 UK units) in the study, 2246 (59%) had ‘COVID-altered’ management. ‘Bridging’ endocrine therapy was used (n = 951) where theatre capacity was reduced. There was increasing access to COVID-19 low-risk theatres during the study period (59%). In line with national guidance, immediate breast reconstruction was avoided (n = 299). Where adjuvant chemotherapy was omitted (n = 81), the median benefit was only 3% (IQR 2–9%) using ‘NHS Predict’. There was the rapid adoption of new evidence-based hypofractionated radiotherapy (n = 781, from 46 units). Only 14 patients (1%) tested positive for SARS-CoV-2 during their treatment journey. Conclusions: The majority of ‘COVID-altered’ management decisions were largely in line with pre-COVID evidence-based guidelines, implying that breast cancer survival outcomes are unlikely to be negatively impacted by the pandemic. However, in this study, the potential impact of delays to BC presentation or diagnosis remains unknown