Constraint on the optical constants of a transparent film on an absorbing substrate for inversion of the ratio of complex p and s reflection coefficients at a given angle of incidence

An absorbing substrate of complex refractive index n2-jk2 can be coated by a transparent thin film of refractive index n1 and normalized thickness ζ so that the ratio of complex reflection coefficients for the pand s polarizations of the film-covered substrate ρ is the inverse of that of the film-free substrate ρ¯ at a given angle of incidence φ. A pair of parallel (metallic) mirrors, one uncoated and the other coated with a ρ-inverting layer, causes a beam displacement without change of polarization and with a certain net reflectance (insertion loss) ℜ. In this paper the constraint on n1,n2,k2 for ρ inversion (ρρ¯ = 1) is represented by a family of constant -n1 contours in the n2k2 plane at φ = 45, 60, and 75°. Along each solution curve, ζ and ℜ are also plottedvs n2 at constant n1. Analysis of the effect of small errors of incidence angles, film refractive index, and thickness is presented for two specific designs using Al mirrors at 650 and 950 nm

Constraint on the optical constants of a transparent film on an absorbing substrate for inversion of the ratio of complex p and s reflection coefficients at a given angle of incidence

An absorbing substrate of complex refractive index n2-jk2 can be coated by a transparent thin film of refractive index n1 and normalized thickness ζ so that the ratio of complex reflection coefficients for the pand s polarizations of the film-covered substrate ρ is the inverse of that of the film-free substrate ρ¯ at a given angle of incidence φ. A pair of parallel (metallic) mirrors, one uncoated and the other coated with a ρ-inverting layer, causes a beam displacement without change of polarization and with a certain net reflectance (insertion loss) ℜ. In this paper the constraint on n1,n2,k2 for ρ inversion (ρρ¯ = 1) is represented by a family of constant -n1 contours in the n2k2 plane at φ = 45, 60, and 75°. Along each solution curve, ζ and ℜ are also plottedvs n2 at constant n1. Analysis of the effect of small errors of incidence angles, film refractive index, and thickness is presented for two specific designs using Al mirrors at 650 and 950 nm

Engineering Trustworthy Self-Adaptive Software with Dynamic Assurance Cases

Building on concepts drawn from control theory, self-adaptive software handles environmental and internal uncertainties by dynamically adjusting its architecture and parameters in response to events such as workload changes and component failures. Self-adaptive software is increasingly expected to meet strict functional and non-functional requirements in applications from areas as diverse as manufacturing, healthcare and finance. To address this need, we introduce a methodology for the systematic ENgineering of TRUstworthy Self-adaptive sofTware (ENTRUST). ENTRUST uses a combination of (1) design-time and runtime modelling and verification, and (2) industry-adopted assurance processes to develop trustworthy self-adaptive software and assurance cases arguing the suitability of the software for its intended application. To evaluate the effectiveness of our methodology, we present a tool-supported instance of ENTRUST and its use to develop proof-of-concept self-adaptive software for embedded and service-based systems from the oceanic monitoring and e-finance domains, respectively. The experimental results show that ENTRUST can be used to engineer self-adaptive software systems in different application domains and to generate dynamic assurance cases for these systems

Contribution of obesity to racial and ethnic disparities in the risk of fetal myelomeningocele: a population-based study.

BACKGROUND: Prepregnancy obesity and racial-ethnic disparities has been shown to be associated with meningomyelocele. OBJECTIVE: This study aimed to investigate the association of maternal periconceptional factors, including race-ethnicity and prepregnancy body mass index, with the prevalence of isolated fetal myelomeningocele. METHODS: This was a population-based cross-sectional study using Centers for Disease Control and Prevention birth data from 2016 to 2021. Major structural anomalies or chromosomal abnormalities were excluded. Race-ethnicity was classified as non-Hispanic White (reference population), non-Hispanic Black, non-Hispanic Asian, Hispanic, and others. Maternal prepregnancy body mass index was classified as underweight (<18.5 kg/m2), normal (reference group; 18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), and class I (30-34.9 kg/m2), class II (35-39.9 kg/m2), and class III obesity (≥40 kg/m2). A chi-square test of independence was performed to identify factors significantly associated with myelomeningocele. These factors were then stratified into 3 adjusted clusters/levels. The prevalence was calculated per 10,000 live births. The Cochran-Armitage test for trend was used to detect any significant increasing or decreasing trends. RESULTS: A total of 22,625,308 pregnancies with live birth, including 2866 pregnancies with isolated fetal myelomeningocele, were included in the analysis. The prevalence of isolated fetal myelomeningocele per 10,000 live births varied among different racial/ethnic groups, with the highest prevalence found among the non-Hispanic White (1.60 [1.52-1.67]) and lowest among the non-Hispanic Asian (0.50 [0.40-0.64]) population. The prevalence significantly increased with body mass index, with the highest prevalence found in the population with class III obesity (1.88 per 10,000 live births). Subgroup analysis of the associations between the significant variables (obesity, diabetes, hypertension, and education) and each ethnicity in cases with myelomeningocele showed significant variations in prevalence of these variables among different racial/ethnic groups. Following the model with the 3 levels of adjustment described in the Methods section, prepregnancy overweight and class I, II, and III obesity remained significantly associated with the odds of isolated fetal myelomeningocele. The adjusted odds ratios were 1.32 (95% confidence interval, 1.19-1.46; P<.001) for overweight, 1.55 (95% confidence interval, 1.38-1.75; P<.001) for class I obesity, 1.68 (95% confidence interval, 1.45-1.94; P<.001) for class II obesity, and 1.73 (95% confidence interval, 1.47-2.04; P<.001) for class III obesity. Similarly, following the 3-level adjustment model, the obesity-mediated effect of maternal race-ethnicity on the odds of myelomeningocele remained significant (non-Hispanic Black: adjusted odds ratio, 1.03; 95% confidence interval, 1.02-1.05; P<.001; non-Hispanic Asian: adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.03; P<.001; Hispanic: adjusted odds ratio, 1.5; 95% confidence interval, 1.03-1.6; P<.001). The test for trend among different racial/ethnic groups did not show significant results across the past 6 years. However, the test for trend showed a significant increase in the prevalence of isolated myelomeningocele associated with class II and III obesity over the past 6 years. CONCLUSION: There has been a rising trend of fetal isolated myelomeningocele in pregnancies with maternal class II and III obesity over the past 6 years after adjusting for other covariates. Prepregnancy obesity, a modifiable risk factor, is a significant driver of racial/ethnic disparities in the overall risk for isolated fetal myelomeningocele

Formal Model-Based Assurance Cases in Isabelle/SACM : An Autonomous Underwater Vehicle Case Study

Isabelle/SACM is a tool for automated construction of model-based assurance cases with integrated formal methods, based on the Isabelle proof assistant. Assurance cases show how a system is safe to operate, through a human comprehensible argument demonstrating that the requirements are satisfied, using evidence of various provenances. They are usually required for certification of critical systems, often with evidence that originates from formal methods. Automating assurance cases increases rigour, and helps with maintenance and evolution. In this paper we apply Isabelle/SACM to a fragment of the assurance case for an autonomous underwater vehicle demonstrator. We encode the metric unit system (SI) in Isabelle, to allow modelling requirements and state spaces using physical units. We develop a behavioural model in the graphical RoboChart state machine language, embed the artifacts into Isabelle/SACM, and use it to demonstrate satisfaction of the requirements

Clinical Study Maternal Hypotension during Fetoscopic Surgery: Incidence and Its Impact on Fetal Survival Outcomes

In this retrospective cohort study, we aimed to determine the incidence of intraoperative maternal hypotension during fetoscopic surgery for twin-twin transfusion syndrome (TTTS) and to evaluate the impact of intraoperative hypotension on fetal survival. A total of 328 TTTS patients with recipient twin cardiomyopathy who underwent fetoscopic surgery under epidural anesthesia were included. The exposure of interest was maternal medical therapy with nifedipine for the treatment of fetal cardiomyopathy. We found that intraoperative hypotension occurred in 53.4% (175/328 patients). There was no statistically significant difference in incidence of hypotension between nifedipine exposure and nonexposure groups (54.8% versus 50.8%, = 0.479). However, the nifedipine exposure group received a statistically significant higher dose of phenylephrine (7.04 ± 6.38 mcg/kg versus 4.70 ± 4.14 mcg/kg, = 0.018) and higher doses of other vasopressor, as counted by number of treatments (6.06 ± 4.58 versus 4.96 ± 3.42, = 0.022). There were no statistically significant differences in acute fetal survival rate (within 5 days) and fetal survival rate at birth between hypotensive and nonhypotensive patients. We concluded that preoperative exposure to nifedipine resulted in increased intraoperative maternal vasopressor requirement during fetoscopic surgery under epidural anesthesia. In patients who had intraoperative maternal hypotension, there was no correlation between the presence of maternal hypotension and postoperative fetal survival

Arabin cervical pessary for prevention of preterm birth in cases of twin-to-twin transfusion syndrome treated by fetoscopic LASER coagulation: the PECEP LASER randomised controlled trial

Abstract Background Fetoscopic LASER coagulation of the placental anastomoses has changed the prognosis of twin-twin transfusion syndrome. However, the prematurity rate in this cohort remains very high. To date, strategies proposed to decrease the prematurity rate have shown inconclusive, if not unfavourable results. Methods This is a randomised controlled trial to investigate whether a prophylactic cervical pessary will lower the incidence of preterm delivery in cases of twin-twin transfusion syndrome requiring fetoscopic LASER coagulation. Women eligible for the study will be randomised after surgery and allocated to either pessary or expectant management. The pessary will be left in place until 37 completed weeks or earlier if delivery occurs. The primary outcome is delivery before 32 completed weeks. Secondary outcomes are a composite of adverse neonatal outcome, fetal and neonatal death, maternal complications, preterm rupture of membranes and hospitalisation for threatened preterm labour. 352 women will be included in order to decrease the rate of preterm delivery before 32 weeks’ gestation from 40% to 26% with an alpha-error of 0.05 and 80% power. Discussion The trial aims at clarifying whether the cervical pessary prolongs the pregnancy in cases of twin-twin transfusion syndrome regardless of cervical length at the time of fetoscopy. Trial registration ClinicalTrials.gov Identifier: NCT01334489 . Registered 04 December 2011

Researching COVID to enhance recovery (RECOVER) pregnancy study: Rationale, objectives and design

Importance Pregnancy induces unique physiologic changes to the immune response and hormonal changes leading to plausible differences in the risk of developing post-acute sequelae of SARS-CoV-2 (PASC), or Long COVID. Exposure to SARS-CoV-2 during pregnancy may also have long-term ramifications for exposed offspring, and it is critical to evaluate the health outcomes of exposed children. The National Institutes of Health (NIH) Researching COVID to Enhance Recovery (RECOVER) Multi-site Observational Study of PASC aims to evaluate the long-term sequelae of SARS-CoV-2 infection in various populations. RECOVER-Pregnancy was designed specifically to address long-term outcomes in maternal-child dyads. Methods RECOVER-Pregnancy cohort is a combined prospective and retrospective cohort that proposes to enroll 2,300 individuals with a pregnancy during the COVID-19 pandemic and their offspring exposed and unexposed in utero, including single and multiple gestations. Enrollment will occur both in person at 27 sites through the Eunice Kennedy Shriver National Institutes of Health Maternal-Fetal Medicine Units Network and remotely through national recruitment by the study team at the University of California San Francisco (UCSF). Adults with and without SARS-CoV-2 infection during pregnancy are eligible for enrollment in the pregnancy cohort and will follow the protocol for RECOVER-Adult including validated screening tools, laboratory analyses and symptom questionnaires followed by more in-depth phenotyping of PASC on a subset of the overall cohort. Offspring exposed and unexposed in utero to SARS-CoV-2 maternal infection will undergo screening tests for neurodevelopment and other health outcomes at 12, 18, 24, 36 and 48 months of age. Blood specimens will be collected at 24 months of age for SARS-CoV-2 antibody testing, storage and anticipated later analyses proposed by RECOVER and other investigators. Discussion RECOVER-Pregnancy will address whether having SARS-CoV-2 during pregnancy modifies the risk factors, prevalence, and phenotype of PASC. The pregnancy cohort will also establish whether there are increased risks of adverse long-term outcomes among children exposed in utero

Inexpensive and Accurate Measuring Device forWater Constitute in Oil

This paper presents an inexpensive and accurate measuring device for water constitute in oil. The new device is based on the relationship between the water constitute in oil and the pressure of a sample from the oil. Experimental results show that the device can attain a very high resolution that can reach up +/- 0.4% and it can be used to measure a full range of water percentage levels (0-100%). Experimental results showed good agreement with theory