What Factors Influence Symptom Reporting and Access to Healthcare During an Emerging Infectious Disease Outbreak? A Rapid Review of the Evidence

During any emerging infectious disease outbreak, people with symptoms of the illness are asked to report to a health service immediately to facilitate contact tracing. Several factors may influence a person's willingness to report symptoms and their ability to access healthcare services. Understanding these factors has become urgent during the COVID-19 pandemic. To determine which factors influence symptom reporting during an emerging infectious disease outbreak, we conducted a rapid review of the evidence. Studies included in the review were based on primary research, published in a peer-reviewed journal, written in English, included factors associated with symptom reporting or accessing healthcare, and were related to a major public health incident involving an infectious disease outbreak. Five themes were identified as facilitators of symptom reporting or accessing healthcare: accurate and informative communication about the disease and the need to seek help, symptom severity, concern about disease exposure, ease of access to healthcare facilities, and relationship with the healthcare provider. Seven themes were identified as barriers to symptom reporting or accessing healthcare: lack of knowledge of the disease and its treatment, fear of the disease and fear of subsequent treatments or requirements, stigmatization attached to having a disease, invasion of privacy, low concern about symptoms, economic consequences of disease diagnosis, and challenges related to attending a healthcare facility. For contract tracing services to be effective, members of the public need to have the capability, opportunity, and motivation to use them. The themes identified should be used to evaluate information provided to the public to ensure as many people as possible with relevant symptoms report them to a healthcare provider

Predictions and Uncertainty Estimates of Reactor Pressure Vessel Steel Embrittlement Using Machine Learning

An essential aspect of extending safe operation of the active nuclear reactors is understanding and predicting the embrittlement that occurs in the steels that make up the Reactor pressure vessel (RPV). In this work we integrate state of the art machine learning methods using ensembles of neural networks with unprecedented data collection and integration to develop a new model for RPV steel embrittlement. The new model has multiple improvements over previous machine learning and hand-tuned efforts, including greater accuracy (e.g., at high-fluence relevant for extending the life of present reactors), wider domain of applicability (e.g., including a wide-range of compositions), uncertainty quantification, and online accessibility for easy use by the community. These improvements provide a model with significant new capabilities, including the ability to easily and accurately explore compositions, flux, and fluence effects on RPV steel embrittlement for the first time. Furthermore, our detailed comparisons show our approach improves on the leading American Society for Testing and Materials (ASTM) E900-15 standard model for RPV embrittlement on every metric we assessed, demonstrating the efficacy of machine learning approaches for this type of highly demanding materials property prediction

Identification of barriers and beliefs influencing engagement by adult and teen Mexican-Americans in oral health behaviors

OBJECTIVE: To identify barriers and beliefs influencing oral health and dental care-seeking among Mexican-Americans. RESEARCH DESIGN: Interviews and Likert-scale survey questions were utilized to explore urgent and preventive dental care-seeking, oral hygiene habits and lifestyle practices. Thirty-three interviews were conducted with 16 adults (ages 33-52), and 17 adolescents (ages 14-19). RESULTS: Teens identified the same main barriers to accessing dental care as adults: high cost, financial limitations and lack of insurance. Most Mexican-Americans agreed with the belief that everyone will need urgent dental treatment and the majority believed that going to a dentist in private practice instead of the Emergency Room was important. Although adults recognized the importance of preventive dental care, half reported being unlikely to seek such care while half of teens reported that they were likely to do so. Adults reported relying equally on themselves and on peers to make dental care decisions, while teens mostly depended on others to make decisions about urgent and preventive care. Virtually all respondents believed regular brushing to be important and many flossing too. A major barrier to flossing was being unsure of the proper technique. Another barrier to better oral health was not having seen messages encouraging changes in lifestyle. CONCLUSIONS: This study found that Mexican-American teens and adults may experience oral health similarly. Teens do not have more positive oral health beliefs and encounter mostly the same barriers to care as adults

Advanced Models of LWR Pressure Vessel Embrittlement for Low Flux-HighFluence Conditions

Neutron embrittlement of reactor pressure vessels (RPVs) is an unresolved issue for light water reactor life extension, especially since transition temperature shifts (TTS) must be predicted for high 80-year fluence levels up to approximately 1,020 n/cm{sup 2}, far beyond the current surveillance database. Unfortunately, TTS may accelerate at high fluence, and may be further amplified by the formation of late blooming phases that result in severe embrittlement even in low-copper (Cu) steels. Embrittlement by this mechanism is a potentially significant degradation phenomenon that is not predicted by current regulatory models. This project will focus on accurately predicting transition temperature shifts at high fluence using advanced physically based, empirically validated and calibrated models. A major challenge is to develop models that can adjust test reactor data to account for flux effects. Since transition temperature shifts depend on synergistic combinations of many variables, flux-effects cannot be treated in isolation. The best current models systematically and significantly under-predict transition temperature at high fluence, although predominantly for irradiations at much higher flux than actual RPV service. This project will integrate surveillance, test reactor and mechanism data with advanced models to address a number of outstanding RPV embrittlement issues. The effort will include developing new databases and preliminary models of flux effects for irradiation conditions ranging from very low (e.g., boiling water reactor) to high (e.g., accelerated test reactor). The team will also develop a database and physical models to help predict the conditions for the formation of Mn-Ni-Si late blooming phases and to guide future efforts to fully resolve this issue. Researchers will carry out other tasks on a best-effort basis, including prediction of transition temperature shift attenuation through the vessel wall, remediation of embrittlement by annealing, and fracture toughness master curve issues

Advanced Models of LWR Pressure Vessel Embrittlement for Low Flux-HighFluence Conditions

Neutron embrittlement of reactor pressure vessels (RPVs) is an unresolved issue for light water reactor life extension, especially since transition temperature shifts (TTS) must be predicted for high 80-year fluence levels up to approximately 1,020 n/cm{sup 2}, far beyond the current surveillance database. Unfortunately, TTS may accelerate at high fluence, and may be further amplified by the formation of late blooming phases that result in severe embrittlement even in low-copper (Cu) steels. Embrittlement by this mechanism is a potentially significant degradation phenomenon that is not predicted by current regulatory models. This project will focus on accurately predicting transition temperature shifts at high fluence using advanced physically based, empirically validated and calibrated models. A major challenge is to develop models that can adjust test reactor data to account for flux effects. Since transition temperature shifts depend on synergistic combinations of many variables, flux-effects cannot be treated in isolation. The best current models systematically and significantly under-predict transition temperature at high fluence, although predominantly for irradiations at much higher flux than actual RPV service. This project will integrate surveillance, test reactor and mechanism data with advanced models to address a number of outstanding RPV embrittlement issues. The effort will include developing new databases and preliminary models of flux effects for irradiation conditions ranging from very low (e.g., boiling water reactor) to high (e.g., accelerated test reactor). The team will also develop a database and physical models to help predict the conditions for the formation of Mn-Ni-Si late blooming phases and to guide future efforts to fully resolve this issue. Researchers will carry out other tasks on a best-effort basis, including prediction of transition temperature shift attenuation through the vessel wall, remediation of embrittlement by annealing, and fracture toughness master curve issues

Development of High-Temperature Ferritic Alloys and Performance Prediction Methods for Advanced Fission Energy Systems

Reports the results of a comprehensive development and analysis of a database on irradiation hardening and embrittlement of tempered martensitic steels (TMS). Alloy specific quantitative semi-empirical models were derived for the dpa dose, irradiation temperature (ti) and test (Tt) temperature of yield stress hardening (or softening)

Calibration of the mixing-length theory for structures of helium-dominated atmosphere white dwarfs

We perform a calibration of the mixing-length parameter at the bottom boundary of the convection zone for helium-dominated atmospheres of white dwarfs. This calibration is based on a grid of 3D DB (pure-helium) and DBA (helium-dominated with traces of hydrogen) model atmospheres computed with the co5bold radiation-hydrodynamics code, and a grid of 1D DB and DBA envelope structures. The 3D models span a parameter space of hydrogen-to-helium abundances in the range −10.0 ≤ log (H/He) ≤−2.0, surface gravities in the range 7.5 ≤ log g ≤ 9.0, and effective temperatures in the range 12 000 K ≲ Teff ≲ 34 000 K. The 1D envelopes cover a similar atmospheric parameter range, but are also calculated with different values of the mixing-length parameter, namely 0.4 ≤ ML2/α ≤ 1.4. The calibration is performed based on two definitions of the bottom boundary of the convection zone: the Schwarzschild and the zero convective flux boundaries. Thus, our calibration is relevant for applications involving the bulk properties of the convection zone including its total mass, which excludes the spectroscopic technique. Overall, the calibrated ML2/α is smaller than what is commonly used in evolutionary models and theoretical determinations of the blue edge of the instability strip for pulsating DB and DBA stars. With calibrated ML2/α we are able to deduce more accurate convection zone sizes needed for studies of planetary debris mixing and dredge-up of carbon from the core. We highlight this by calculating examples of metal-rich 3D DBAZ models and finding their convection zone masses. Mixing-length calibration represents the first step of in-depth investigations of convective overshoot in white dwarfs with helium-dominated atmospheres

Vibrational properties of SrCu2O2 studied via Density Functional Theory calculations and compared to Raman and infrared spectroscopy measurements

International audienceThe SrCu2O2 material is a p-type transparent conductive oxide. A theoretical study of the SrCu2O2 crystal is performed with a state of the art implementation of the Density Functional Theory. The simulated crystal structure is compared with available X-ray diffraction data and previous theoretical modeling. Density Functional Perturbation Theory is used to study the vibrational properties of the SrCu2O2 crystal. A symmetry analysis of the optical phonon eigenvectors at the Brillouin zone center is proposed. The Raman spectra simulated using the derivatives of the dielectric susceptibility, show a good agreement with Raman scattering experimental results