1,684 research outputs found
Investigation into Stability, Transition and Turbulence of Thermal Plumes
In this thesis, the stability, transition and turbulence of thermal plumes were investigated by numerical simulation. Experiments were also conducted, but only for the validation of the simulation code being used. The effect of variable transport properties on a large eddy simulation of a turbulent axisymmetric plume was examined, and it was shown that an in-house incompressible Navier-Stokes solver, which is based on a standard Smagorinsky LES model, with the effects of variable properties incorporated using a modified Sutherlands law, predicts the correct statistical behaviours of the turbulent plume. The near-field puffing instability in thermal planar plumes, which had received little attention in the literature, was investigated by direct numerical simulation. The associated lapping flow instability, forming bulge structures over a heated floor section, was studied using a channel flow model, which allows the lapping flow velocity to be varied. The parametric dependencies were found for the bulge formation and the oscillation frequencies in the lapping flow. Further, the Prandtl number dependent transitional behaviours in the near-field were investigated, and direct stability analysis was conducted to study the lapping flow and stem instabilities. Experiments using a shadowgraph technique and an in-house, two-dimensional, two-component particle image velocimetry, with water as the working fluid, provided validations for the near-field unsteady behaviours of thermal plumes. A ventilated filling box flow with a transitional planar plume was also investigated by direct numerical simulation. A mapping of transitional flow behaviours was obtained, and the parametric dependencies of turbulence statistics and mean flow characteristics were investigated. The three-dimensionality was shown to have only minor effects on the transitional ventilated filling box flows being considered
Probing problems and priorities in oral health (care) among community dwelling elderly in the Netherlands: a mixed method study
Background: Complex dentitions and decline in adequate oral hygiene in elderly may lead to poor oral health. This may have impact on their general health, wellbeing and quality of life. With increased longevity, the problems and needs in oral health of community dwelling elderly lead to changes in oral health care needs. We identified and prioritized problems and needs in oral health of community dwelling elderly. Methods: The problems and needs in oral health of community dwelling elderly were elicited during focus groups and interviews. The list of problems and needs derived thereof was presented to 97 elderly who prioritized these. Results: Overall, older people appeared to be satisfied with their current oral health, and the maintenance and care for their oral health. Cost of care was identified as a major problem in general. There are differences in current perceived problems and needs and problems and needs anticipated for the future. Perceived current problems and needs concern dental care provision and knowledge on oral health of professionals and patients. For anticipated future problems and needs the importance of daily oral care by caregivers was prioritised, while emphasis was placed on fear of losing autonomy. Conclusion: It is important to take the perspectives and expectations of elderly into account in policy and planning of future oral health care practice, because these differ from the perspectives of dental professionals
Indicators of affective empathy, cognitive empathy and social attention during emotional clips in relation to aggression in three-year-olds
Research indicates that impaired empathy is a risk factor of aggression and that social attention is important for empathy. The role of social attention in associations between empathy and aggression has not yet been fully elucidated. Therefore, indicators of affective empathy, cognitive empathy, social attention, and aggression were simultaneously assessed in children aged 45âŻmonths. A total of 61 motherâchild dyads participated in a lab visit, during which maternal reports of aggression were obtained. Children watched three clips showing a sad, scared, and happy child, respectively, and a neutral social clip while heart rate was recorded. Heart rate change from nonsocial baseline clips to emotional clips was calculated as an index of affective empathy. Questions about the emotions of the children in the clips were asked to assess cognitive empathy. Social attention was defined as time spent looking at faces during the clips. Correlation analyses revealed negative associations between affective empathy and aggression and between social attention and aggression. Furthermore, multivariate linear regression analyses indicated that the association between affective empathy and aggression was moderated by social attention; the negative association between affective empathy and aggression was stronger in children with relatively reduced social attention. No association was found between cognitive empathy and aggression. Therefore, both affective empathy and social attention are important targets for early interventions that aim to prevent or reduce aggression
Infant parasympathetic and sympathetic activity during baseline, stress and recovery: interactions with prenatal adversity predict physical aggression in toddlerhood
Exposure to prenatal adversity is associated with aggression later in life. Individual differences in autonomic nervous system (ANS) functioning, specifically nonreciprocal activation of the parasympathetic (PNS) and sympathetic (SNS) nervous systems, increase susceptibility to aggression, especially in the context of adversity. Previous work examining interactions between early adversity and ANS functioning in infancy is scarce and has not examined interaction between PNS and SNS. This study examined whether the PNS and SNS moderate the relation between cumulative prenatal risk and early physical aggression in 124 children (57% male). Cumulative risk (e.g., maternal psychiatric disorder, substance (ab)use, and social adversity) was assessed during pregnancy. Parasympathetic respiratory sinus arrhythmia (RSA) and sympathetic pre-ejection period (PEP) at baseline, in response to and during recovery from emotional challenge were measured at 6 months. Physical aggression and non-physical aggression/oppositional behavior were measured at 30 months. The results showed that cumulative prenatal risk predicted elevated physical aggression and non-physical aggression/oppositional behavior in toddlerhood; however, the effects on physical aggression were moderated by PNS and SNS functioning. Specifically, the effects of cumulative risk on physical aggression were particularly evident in children characterized by low baseline PNS activity and/or by nonreciprocal activity of the PNS and SNS, characterized by decreased activity (i.e., coinhibition) or increased activity (i.e., coactivation) of both systems at baseline and/or in response to emotional challenge. These findings extend our understanding of the interaction between perinatal risk and infant ANS functioning on developmental outcome
Scenario planning for the Edinburgh city region
This paper examines the application of scenario planning techniques to the detailed and daunting challenge of city re-positioning when policy makers are faced with a heavy history and a complex future context. It reviews a process of scenario planning undertaken in the Edinburgh city region, exploring the scenario process and its contribution to strategies and policies for city repositioning. Strongly rooted in the recent literature on urban and regional economic development, the text outlines how key individuals and organisations involved in the process participated in far-reaching analyses of the possible future worlds in which the Edinburgh city region might find itself
InP-based two-dimensional photonic crystals filled with polymers
Polymer filling of the air holes of Indium Phosphide based two-dimensional
photonic crystals is reported. After infiltration of the holes with a liquid
monomer and solidification of the infill in situ by thermal polymerization,
complete filling is proven using scanning electron microscopy. Optical
transmission measurements of a filled photonic crystal structure exhibit a
redshift of the air band, confirming the complete filling.Comment: To be published in Appl. Phys. Let
Measurement with Persons: A European Network
The European âMeasuring the Impossibleâ Network MINET promotes new research activities in measurement dependent on human perception and/or interpretation. This includes the perceived attributes of products and services, such as quality or desirability, and societal parameters such as security and well-being. Work has aimed at consensus about four âgenericâ metrological issues: (1) Measurement Concepts & Terminology; (2) Measurement Techniques: (3) Measurement Uncertainty; and (4) Decision-making & Impact Assessment, and how these can be applied specificallyto the âMeasurement of Personsâ in terms of âMan as a Measurement Instrumentâ and âMeasuring Man.â Some of the main achievements of MINET include a research repository with glossary; training course; book; series of workshops;think tanks and study visits, which have brought together a unique constellation of researchers from physics, metrology,physiology, psychophysics, psychology and sociology. Metrology (quality-assured measurement) in this area is relativelyunderdeveloped, despite great potential for innovation, and extends beyond traditional physiological metrology in thatit also deals with measurement with all human senses as well as mental and behavioral processes. This is particularlyrelevant in applications where humans are an important component of critical systems, where for instance health andsafety are at stake
Exploring Associations between Oral Health and Frailty in Community-Dwelling Older People
BACKGROUND: In frail older people with natural teeth factors like polypharmacy, reduced salivary flow, a decrease of oral self-care, general healthcare issues, and a decrease in dental care utilization contribute to an increased risk for oral complications. On the other hand, oral morbidity may have a negative impact on frailty. OBJECTIVE: This study explored associations between oral health and two frailty measures in community-dwelling older people. DESIGN: A cross-sectional study. SETTING: The study was carried out in a Primary Healthcare Center (PHC) in The Netherlands. PARTICIPANTS: Of the 5,816 persons registered in the PHC, 1,814 persons were eligible for participation at the start of the study. MEASUREMENTS: Two frailty measures were used: 1. Being at risk for frailty, using Electronical Medical Record (EMR) data, and: 2. Survey-based frailty using 'The Groningen Frailty Indicator' (GFI). For oral health measures, dental-record data (dental care utilization, dental status, and oral health information) and self-reported oral problems were recorded. Univariate regression analyses were applied to determine the association between oral health and frailty, followed by age- and sex-adjusted multivariate logistic regressions. RESULTS: In total 1,202 community-dwelling older people were included in the study, 45% were male and the mean age was 73 years (SD=8). Of all participants, 53% was at risk for frailty (638/1,202), and 19% was frail based on the GFI (222/1,202). A dental emergency visit (Odds Ratio (OR)= 2.0, 95% Confidence Interval (CI)=1.33;3.02 and OR=1.58, 95% CI=1.00;2.49), experiencing oral problems (OR=2.07, 95% CI=1.52;2.81 and OR=2.87, 95% CI= 2.07;3.99), and making dietary adaptations (OR=2.66, 95% CI=1.31;5.41 and OR=5.49, 95% CI= 3.01;10.01) were associated with being at risk for frailty and survey-based frailty respectively. CONCLUSIONS: A dental emergency visit and self-reported oral health problems are associated with frailty irrespective of the approach to its measurement. Healthcare professionals should be aware of the associations of oral health and frailty in daily practice
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