Supermassive Black-hole Demographics & Environments With Pulsar Timing Arrays

Precision timing of large arrays (>50) of millisecond pulsars will detect the nanohertz gravitational-wave emission from supermassive binary black holes within the next ~3-7 years. We review the scientific opportunities of these detections, the requirements for success, and the synergies with electromagnetic instruments operating in the 2020s.Comment: Submitted to the Astro2020 Decadal Survey. One of 5 core white-papers authored by members of the NANOGrav Collaboration. 9 pages, 2 figure

The role of psychosocial factors and treatment need in dental service use and oral health among adults in Norway

Objectives - This study aimed to explore whether population characteristics were associated with the use of dental services, individual's personal oral health practices, dental caries and oral health‐related impacts using the revised Andersen's behavioural model as the theoretical framework. Methods - This cross‐sectional study included participants from a Norwegian general population (N = 1840; 20‐79 years) included in the Tromstannen—Oral Health in Northern Norway (TOHNN) study. The variables included in the model were social structure (income, education, urbanization), sense of coherence (SOC), enabling resources (difficulties accessing the dentist, declined treatment, dental anxiety), treatment need, use of dental services, toothbrushing frequency, sugary soda drink consumption, decayed teeth and oral health‐related impacts (OHIP‐14). Structural equation modelling was used to test the direct and indirect effects within Andersen's behavioural model of access and health outcomes. Results - Andersen's behavioural model fit the data well and explained a large part of the variance in use of dental services (58%), oral health‐related impacts (48%) and, to a lesser extent, decayed teeth (12%). More social structures and a stronger SOC was associated with more enabling resources, which in turn, was associated with more use of dental services. Social structures were not directly associated with use of dental services or decayed teeth but were predictive of oral health‐related impacts. A stronger SOC was associated with more frequent toothbrushing, less soda drink consumptions, fewer decayed teeth and less oral health‐related impacts. Self‐perceived need did not predict dental attendance but was associated with decayed teeth. A less frequent use of dental services, less frequent toothbrushing and more frequent sugary soda drink consumption were associated with more decayed teeth. Decayed teeth were not associated with oral health‐related impacts. Conclusion - The findings suggests that, in addition to focusing on reducing socioeconomic inequalities in relation to oral health in the Norwegian population, it is also important to consider how people perceive their own resources (eg financial, psychological, social) as well as their access to dental care in order to support regular dental attendance and potentially, in turn, enhance oral health

Polypeptide translocation by the AAA+ ClpXP protease machine

In the AAA+ ClpXP protease, ClpX uses repeated cycles of ATP hydrolysis to pull native proteins apart and to translocate the denatured polypeptide into ClpP for degradation. Here, we probe polypeptide features important for translocation. ClpXP degrades diverse synthetic peptide substrates despite major differences in side-chain chirality, size, and polarity. Moreover, translocation occurs without a peptide –NH and with 10 methylenes between successive peptide bonds. Pulling on homopolymeric tracts of glycine, proline, and lysine also allows efficient ClpXP degradation of a stably folded protein. Thus, minimal chemical features of a polypeptide chain are sufficient for translocation and protein unfolding by the ClpX machine. These results suggest that the translocation pore of ClpX is highly elastic, allowing interactions with a wide range of chemical groups, a feature likely to be shared by many AAA+ unfoldases.National Institutes of Health (U.S.) (AI-15706

How and why we need to capture tacit knowledge in manufacturing: Case studies of visual inspection

Human visual inspection skills remain superior for ensuring product quality and conformance to standards in the manufacturing industry. However, at present these skills cannot be formally shared with other workers or used to develop and implement new solutions or assistive technologies because they involve a high level of tacit knowledge which only exists in skilled operators' internal cognitions. Industry needs reliable methods for the capture and analysis of this tacit knowledge so that it can be shared and not lost but also so that it can be best utilised in the transfer of manual work to automated systems and introduction of new technologies and processes. This paper describes two UK manufacturing case studies that applied systematic task analysis methods to capture and scrutinise the tacit knowledge and skills being applied in the visual inspection of aerospace components. Results reveal that the method was effective in eliciting tacit knowledge, and showed that tacit skills are particularly needed when visual inspection standards lack specification or the task requires greater subjective interpretation. The implications of these findings for future research and for developments in the manufacturing industry are discussed

Are oral health conditions associated with schoolchildren’s performance and school attendance in the Kingdom of Bahrain? A life-course perspective

Background: The link between oral diseases and school performance and school attendance remains unclear among Middle Eastern children.Aim: To investigate the relationship of oral conditions with schoolchildren's school performance and attendance using the life- course approach.Design: A cross- sectional study was conducted with 466 schoolchildren aged 7- 8 years from Kingdom of Bahrain (KoB) and their parents. Questionnaire data on children's current and at- birth environmental characteristics were completed by their parents. Children's oral health measures, including ICDAS (International Caries Detection and Assessment System), PUFA (pulp, ulcer, fistula, abscess), and DDE (developmental defects of enamel) indices, were the exposure variables. School performance and school attendance data obtained from the school register were the outcome variables. The data were analysed using multivariate ordinal logistic regression.Results: The odds of excellent school performance were significantly lower for children with untreated dentinal caries (OR = 0.98; 95% CI: 0.96- 0.99). Children with caries- treated teeth showed greater odds of excellent school performance (OR = 1.41; 95% CI: 1.15- 1.74). Disease Control and PreventionNone of the den-tal conditions were significantly associated with children’s school attendance. A permissive parental style was associated with poor school attendance (OR = 2.63; 95% CI: 1.08- 6.42).Conclusion: Dental caries was associated with poor school performance but not with school attendance. Treated caries was associated with good school performance.acceptedVersio

Preliminary Investigation of Tracer Gas Reaeration Method for Shallow Bays

Accurate estimates of surface exchange rates for volatile pollutants in bays are needed to allow predictions of pollutant movement and retention time. The same types of estimates can be used to calculate reaeration rates. The tracer gas technique has been used to measure surface gas transfer rates in rivers, and to a lesser extent, in estuaries. Application of the technique to bays would be extremely useful, but it is complicated by differences in the hydrodynamics and the density stratification that can exist due to fresh river water overriding heavier saline ocean water. The objective of this research has been to investigate field procedures for application of the tracer gas technique to shallow bays. The modified tracer technique was used with propane for the tracer gas and Rhodamine-WT, a fluorescent dye, for the "conservative" tracer. The propane was injected through porous tile diffusers, and the dye was released simultaneously. The propane acts as a model for the surface exchange of other gases and volatile compounds. Three four-day field trips to Lavaca Bay on the Texas coast of the Gulf of Mexico were made during the course of the study. A variety of experimental techniques was investigated. One was to make a short-duration injection (10-30 minutes) and sample the dye cloud as it moved through the bay. Another was to use a long-duration injection (3 to 4 hours) to obtain quasi-steady conditions. The long injections were discontinued because there appeared to be no practical method of determining the travel time for the samples taken from the tracer plume. Drogues (floats) which are normally used for this purpose consistently drifted downwind from the tracer plumes. Pulses of a second fluorescent dye for determining time of travel became too diffuse to be used for this purpose. The most promising method appears to be the short-duration injection method with a large pulse of the second dye released during the injection to mark the middle of the tracer cloud. A special injection device was designed to prevent mixing of the tracers with heavier saline water near the bed of the bay during injection. A field fluorometer was used both in the field to track the tracer cloud and in the laboratory to measure dye concentrations in the field samples. Propane concentrations were determined with gas chromatography. The same equipment was used to perform laboratory studies to test performance of the equipment in the field and to aid in understanding field test results. These were apparently the first tests to be performed using the tracer gas technique in bays. As a result, the emphasis was on the development of techniques rather than on obtaining data. It appears that workable techniques have been developed, but they now need to be tested under a variety of conditions. Also, the preliminary results which were obtained for gas transfer coefficients indicate some anomalous results. After the completion of the project, it was learned that the addition of formalin to the field tracer gas samples may be affecting the samples adversely. Thus, some laboratory tests are now needed to investigate the behavior of tracer gases in bay water. In summary, the method appears to be very promising, but some additional developmental work is required before it can be used on a routine basi

Standardised Practice-Based Oral Health Data Collection: A Pilot Study in Different Countries

BACKGROUND: The Oral Health Observatory (OHO), launched in 2014 by FDI World Dental Federation, aims to provide a coordinated approach to international oral health data collection. A feasibility project involving 12 countries tested the implementation of the methodology and data collection tools and assessed data quality from 6 countries. METHODS: National dental associations (NDAs) recruited dentists following a standardised sampling method. Dentists and patients completed paired questionnaires (N = 7907) about patients' demographics, dental attendance, oral health-related behaviours, oral impacts, and clinical measures using a mobile app. In addition, participating dentists (n = 93) completed an evaluation survey, and NDAs completed a survey and participated in workshops to assess implementation feasibility. RESULTS: Feasibility data are presented from the 12 participating countries. In addition, the 6 countries most advanced with data collection as of July 2020 (China, Colombia, India, Italy, Japan, and Lebanon) were included in the assessment of data quality and qualitative evaluation of implementation feasibility. All NDAs in these 6 countries reported interest in collecting standardised, international data for policy and communication activities and to understand service use and needs. Eighty-two percent of dentists (n = 76) reported a patient response rate of between 80% and 100%. More than 70% (n = 71) of dentists were either satisfied or very satisfied with the patient recruitment and data collection methods. There were variations in patient oral health and behaviours across countries, such as self-reporting twice-daily brushing which ranged from 45% in India to 83% in Colombia. CONCLUSIONS: OHO provides a feasible model for collecting international standardised data in dental practices. Reducing time implications, ensuring mobile app reliability, and allowing practitioners to access patient-reported outcomes to inform practice may enhance implementation