531 research outputs found
Dynamics of precipitation pattern formation at geothermal hot springs
We formulate and model the dynamics of spatial patterns arising during the
precipitation of calcium carbonate from a supersaturated shallow water flow.
The model describes the formation of travertine deposits at geothermal hot
springs and rimstone dams of calcite in caves. We find explicit solutions for
travertine domes at low flow rates, identify the linear instabilities which
generate dam and pond formation on sloped substrates, and present simulations
of statistical landscape evolution
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Application of Two-Parameter Item Response Theory for Determining Form-Dependent Items on Exams Using Different Item Orders
Using multiple versions of an assessment has the potential to introduce item environment effects. These types of effects result in version dependent item characteristics (i.e., difficulty and discrimination). Methods to detect such effects and resulting implications are important for all levels of assessment where multiple forms of an assessment are created. This report describes a novel method for identifying items that do and do not display form dependence. The first two steps identify form dependent items using a differential item functioning (DIF) analysis of item parameters estimated by Item Response Theory. The method is illustrated using items that appeared in four forms (two trial and two released versions) of a first semester general chemistry examination. Eighteen of fifty-six items were identified as having item parameters that were form dependent. Thirteen of those items displayed a form dependence consistent with reasons previously identified in the literature: preceding item difficulty, content priming, and a combination of preceding item difficulty and content priming. The remaining five items had form dependence that did not align reasons reported in the literature. An analysis was done to determine if all possible instances of predicted form dependence could be found. Several instances where form dependence could have been found, based on the preceding item difficulty or content priming, were identified, and those items did not display form dependence. We identify and rationalize form dependence for thirteen of the eighteen items flagged; however, we are unable to predict form dependence for items
Listeria monocytogenes Invades the Epithelial Junctions at Sites of Cell Extrusion
Listeria monocytogenes causes invasive disease by crossing the intestinal epithelial barrier. This process depends on the interaction between the bacterial surface protein Internalin A and the host protein E-cadherin, located below the epithelial tight junctions at the lateral cell-to-cell contacts. We used polarized MDCK cells as a model epithelium to determine how L. monocytogenes breaches the tight junctions to gain access to this basolateral receptor protein. We determined that L. monocytogenes does not actively disrupt the tight junctions, but finds E-cadherin at a morphologically distinct subset of intercellular junctions. We identified these sites as naturally occurring regions where single senescent cells are expelled and detached from the epithelium by extrusion. The surrounding cells reorganize to form a multicellular junction that maintains epithelial continuity. We found that E-cadherin is transiently exposed to the lumenal surface at multicellular junctions during and after cell extrusion, and that L. monocytogenes takes advantage of junctional remodeling to adhere to and subsequently invade the epithelium. In intact epithelial monolayers, an anti-E-cadherin antibody specifically decorates multicellular junctions and blocks L. monocytogenes adhesion. Furthermore, an L. monocytogenes mutant in the Internalin A gene is completely deficient in attachment to the epithelial apical surface and is unable to invade. We hypothesized that L. monocytogenes utilizes analogous extrusion sites for epithelial invasion in vivo. By infecting rabbit ileal loops, we found that the junctions at the cell extrusion zone of villus tips are the specific target for L. monocytogenes adhesion and invasion. Thus, L. monocytogenes exploits the dynamic nature of epithelial renewal and junctional remodeling to breach the intestinal barrier
Living well with dementia: An exploratory matched analysis of minority ethnic and white people with dementia and carers participating in the IDEAL programme
Objectives: The increasing heterogeneity of the population of older people is reflected in an increasing number of people with dementia and carers drawn from minority ethnic groups. Data from the IDEAL study are used to compare indices of ‘living well’ among people with dementia and carers from ethnic minority groups with matched white peers. Methods: We used an exploratory cross-sectional case-control design to compare ‘living well’ for people with dementia and carers from minority ethnic and white groups. Measures for both groups were quality of life, life satisfaction, wellbeing, loneliness, and social isolation and, for carers, stress, relationship quality, role captivity and caring competence. Results: The sample of people with dementia consisted of 20 minority ethnic and 60 white participants and for carers 15 and 45 respectively. People with dementia from minority ethnic groups had poorer quality of life (−4.74, 95% CI: −7.98 to −1.50) and higher loneliness (1.72, 95% CI: 0.78–2.66) whilst minority ethnic carers had higher stress (8.17, 95% CI: 1.72–14.63) and role captivity (2.00, 95% CI: 0.43–3.57) and lower relationship quality (−9.86, 95% CI: −14.24 to −5.48) than their white peers. Conclusion: Our exploratory study suggests that people with dementia from minority ethnic groups experience lower quality of life and carers experience higher stress and role captivity and lower relationship quality than their white peers. Confirmatory research with larger samples is required to facilitate analysis of the experiences of specific minority ethnic groups and examine the factors contributing to these disadvantages
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Are profiles of social, cultural, and economic capital related to living well with dementia? Longitudinal findings from the IDEAL cohort
Copyright © 2022 Rationale:
Research exploring social, cultural, and economic capital among people with dementia is scarce.
Objective:
We describe levels of social, cultural, and economic capital in people with dementia at baseline and levels of social and cultural capital 12 and 24 months later. We identify groups of people with dementia having different combinations of capital and explore whether the identified groups differ in personal characteristics at baseline and in quality of life (QoL), satisfaction with life (SwL), and well-being over time.
Method:
Baseline, 12-months, and 24-months data from 1537 people with dementia (age, mean = 76.4 years; SD = 8.5; Alzheimer's Disease = 55.4%) enrolled in the IDEAL cohort were analyzed. Social (interactions with friends, civic participation, social participation, neighborhood trust, social network), cultural (education, cultural participation) and economic (annual income) capital, QoL, SwL, well-being, and personal characteristics were assessed.
Results:
Compared to people their age, people with dementia reported slightly lower frequency of interactions with friends, social networks and social support, civic and cultural participation, education, and annual income. However, social engagement, cultural participation, and annual income are low among British older adults. Latent profile analysis identified four groups that, based on their levels of social, cultural, and economic capital were named socially and economically privileged (18.0% of participants); financially secure (21.0% of participants); low capital (36.9% of participants); and very low capital (24.1% of participants). Latent growth curve models showed that over time QoL, SwL, and well-being remained largely stable for all groups. Compared to the low capital group, the socially and economically privileged and financially secure groups had higher QoL and well-being whereas the group with very low capital had poorer QoL, SwL, and well-being.
Conclusions:
New policies and efforts from the government, philanthropic foundations, the voluntary and primary care sectors are needed to address social, cultural, and economic disadvantage among people with dementia.Economic and Social Research Council (ESRC) and the National Institute for Health and Care Research (NIHR) through grant ES/L001853/2. Alzheimer's Society, grant number 348, AS-PR2-16-001
Methods and approaches for enhancing communication with people with moderate-to-severe dementia that can facilitate their inclusion in research and service evaluation: Findings from the IDEAL programme
This is the final version. Available on open access from SAGE Publications via the DOI in this recordOBJECTIVES: Dementia can affect language processing and production, making communication more difficult. This creates challenges for including the person's perspective in research and service evaluation. This study aims to identify methods, tools and approaches that could facilitate meaningful communication with people with moderate-to-severe dementia and support the inclusion of their perspectives. METHODS: This qualitative study was conducted as part of the IDEAL programme and involved in-depth, semi-structured interviews with 17 dementia research and/or care professionals with expertise in communication. Transcripts were analysed using framework analysis. FINDINGS: Three main themes each with sub-themes were identified: (1) Awareness, knowledge and experience; (2) Communication approach and (3) Personalization. A person-centred orientation based on getting to know the participant and developing a bi-directional exchange formed the fundamental context for effective communication. Building on this foundation, an approach using pictures, photographs or objects that are meaningful to the person and appropriate for that person's preferences and ability could help to facilitate conversations. The findings were integrated into a diagram illustrating how the topics covered by the themes interrelate to facilitate communication. CONCLUSIONS: Useful skills and approaches were identified to help researchers engage and work with people with moderate-to-severe dementia and ensure their perspective is included. These covered getting to know the participant, using a variety of tangible tools and interactional techniques and considering the environment and context of the conversation.Alzheimer's SocietyEconomic and Social Research Council (ESRC)National Institute for Health Research (NIHR
Methods and approaches for enhancing communication with people with moderate-to-severe dementia that can facilitate their inclusion in research and service evaluation findings from the IDEAL programme
YesObjectives
Dementia can affect language processing and production, making communication more difficult. This creates challenges for including the person’s perspective in research and service evaluation. This study aims to identify methods, tools and approaches that could facilitate meaningful communication with people with moderate-to-severe dementia and support the inclusion of their perspectives.
Methods
This qualitative study was conducted as part of the IDEAL programme and involved in-depth, semi-structured interviews with 17 dementia research and/or care professionals with expertise in communication. Transcripts were analysed using framework analysis.
Findings
Three main themes each with sub-themes were identified: (1) Awareness, knowledge and experience; (2) Communication approach and (3) Personalization. A person-centred orientation based on getting to know the participant and developing a bi-directional exchange formed the fundamental context for effective communication. Building on this foundation, an approach using pictures, photographs or objects that are meaningful to the person and appropriate for that person’s preferences and ability could help to facilitate conversations. The findings were integrated into a diagram illustrating how the topics covered by the themes interrelate to facilitate communication.
Conclusions
Useful skills and approaches were identified to help researchers engage and work with people with moderate-to-severe dementia and ensure their perspective is included. These covered getting to know the participant, using a variety of tangible tools and interactional techniques and considering the environment and context of the conversation.ESRC, NIHR (ES/L001853/2); Alzheimer's Society (348, AS-PR2-16-001
Are profiles of social, cultural, and economic capital related to living well with dementia? Longitudinal findings from the IDEAL programme
Rationale: Research exploring social, cultural, and economic capital among people with dementia is scarce. Objective: We describe levels of social, cultural, and economic capital in people with dementia at baseline and levels of social and cultural capital 12 and 24 months later. We identify groups of people with dementia having different combinations of capital and explore whether the identified groups differ in personal characteristics at baseline and in quality of life (QoL), satisfaction with life (SwL), and well-being over time. Method: Baseline, 12-months, and 24-months data from 1537 people with dementia (age, mean = 76.4 years; SD = 8.5; Alzheimer's Disease = 55.4%) enrolled in the IDEAL cohort were analyzed. Social (interactions with friends, civic participation, social participation, neighborhood trust, social network), cultural (education, cultural participation) and economic (annual income) capital, QoL, SwL, well-being, and personal characteristics were assessed. Results: Compared to people their age, people with dementia reported slightly lower frequency of interactions with friends, social networks and social support, civic and cultural participation, education, and annual income. However, social engagement, cultural participation, and annual income are low among British older adults. Latent profile analysis identified four groups that, based on their levels of social, cultural, and economic capital were named socially and economically privileged (18.0% of participants); financially secure (21.0% of participants); low capital (36.9% of participants); and very low capital (24.1% of participants). Latent growth curve models showed that over time QoL, SwL, and well-being remained largely stable for all groups. Compared to the low capital group, the socially and economically privileged and financially secure groups had higher QoL and well-being whereas the group with very low capital had poorer QoL, SwL, and well-being. Conclusions: New policies and efforts from the government, philanthropic foundations, the voluntary and primary care sectors are needed to address social, cultural, and economic disadvantage among people with dementia
Methods and approaches to facilitate inclusion of the views, perspectives and preferences of people with moderate-to-severe dementia in research: a mixed-methods systematic review
YesBackground: The perspectives of people with moderate-to-severe dementia are rarely directly elicited in research studies.
Objectives: This systematic review will explore methods and approaches for including the perspectives and preferences of people with moderate-to-severe dementia in research.
Methods: AgeLine, CINAHL, Embase, PsycINFO, PubMed, Social Policy and Practice and Web of Science were searched until June 16 2022. Study quality was assessed using the 16-item Quality Assessment Tool. We described specific communication tools, reviewed the evidence for their effectiveness and considered their strengths and limitations. We examined the more general communication skills and techniques applied to support the use of these tools using thematic synthesis. The review protocol was registered with PROSPERO CRD42019130386 and the review was conducted and reported according to PRISMA guidelines.
Results: Seven studies reported in 11 publications were included. In these studies five specific communication tools were used: Talking Mats, Augmentative and Alternative Communication Flexiboard, generic photographs in combination with a preference placement board, consultation ballot and personalised communication prescriptions. Each tool identified had advantages and disadvantages depending on dementia severity, verbal or physical ability, expense, researcher training requirements and ease of use. Thematic synthesis identified five general approaches to optimising communication that were employed to support use of the tools: ensuring conversations are individual and person-centred, managing external influences, engaging others, creating structure and facilitation skills.
Conclusion: All tools had some utility and there was no clear evidence to support the recommendation of any one specific tool; therefore, researchers are advised to select the tool most appropriate to their context.
Implications for Practice: The findings offer general guidance for researchers and practitioners on how to facilitate communication with people with moderate-to-severe dementia.Alzheimer's Society. Grant Number: AS-PR2-16-001. National Institute for Health and Care Research. Grant Number: ES/L001853/2. UK Research and Innovation. Grant Number: ES/L001853/
Dyadic perspectives on loneliness and social isolation among people with dementia and spousal carers: findings from the IDEAL programme
YesThis study aims to investigate the impact of self and partner experiences of loneliness and social isolation on life satisfaction in people with dementia and their spousal carers.
We used data from 1042 dementia caregiving dyads in the Improving the experience of Dementia and Enhancing Active Life (IDEAL) programme cohort. Loneliness was measured using the six-item De Jong Gierveld loneliness scale and social isolation using the six-item Lubben Social Network Scale. Data were analysed using the Actor-Partner Interdependence Model framework.
Self-rated loneliness was associated with poorer life satisfaction for both people with dementia and carers. The initial partner effects observed between the loneliness of the carer and the life satisfaction of the person with dementia and between social isolation reported by the person with dementia and life satisfaction of the carer were reduced to nonsignificance once the quality of the relationship between them was considered.
Experiencing greater loneliness and social isolation is linked with reduced life satisfaction for people with dementia and carers. However, having a positive view of the quality of the relationship between them reduced the impact of loneliness and social isolation on life satisfaction. Findings suggest the need to consider the experiences of both the person with dementia and the carer when investigating the impact of loneliness and social isolation. Individual interventions to mitigate loneliness or isolation may enhance life satisfaction for both partners and not simply the intervention recipient.‘Improving the experience of Dementia and Enhancing Active Life: living well with dementia. The IDEAL study’ was funded jointly by the Economic and Social Research Council (ESRC) and the National Institute for Health and Care Research (NIHR) through grant ES/L001853/2. ‘Improving the experience of Dementia and Enhancing Active Life: a longitudinal perspective on living well with dementia. The IDEAL-2 study’ is funded by Alzheimer’s Society, grant number 348, AS-PR2-16- 001
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