Map matching queries on realistic input graphs under the Fr\'echet distance

Map matching is a common preprocessing step for analysing vehicle trajectories. In the theory community, the most popular approach for map matching is to compute a path on the road network that is the most spatially similar to the trajectory, where spatial similarity is measured using the Fr\'echet distance. A shortcoming of existing map matching algorithms under the Fr\'echet distance is that every time a trajectory is matched, the entire road network needs to be reprocessed from scratch. An open problem is whether one can preprocess the road network into a data structure, so that map matching queries can be answered in sublinear time. In this paper, we investigate map matching queries under the Fr\'echet distance. We provide a negative result for geometric planar graphs. We show that, unless SETH fails, there is no data structure that can be constructed in polynomial time that answers map matching queries in $O((pq)^{1-\delta})$ query time for any $\delta > 0$, where $p$ and $q$ are the complexities of the geometric planar graph and the query trajectory, respectively. We provide a positive result for realistic input graphs, which we regard as the main result of this paper. We show that for $c$-packed graphs, one can construct a data structure of $\tilde O(cp)$ size that can answer $(1+\varepsilon)$-approximate map matching queries in $\tilde O(c^4 q \log^4 p)$ time, where $\tilde O(\cdot)$ hides lower-order factors and dependence of $\varepsilon$.Comment: To appear in SODA 202

Carbon dioxide accounting:2014 Commonwealth Games Atheletes’ Village

A spreadsheet-based tool for whole-life carbon dioxide accounting of soil remediation projects has been created. The tool carries out whole-life analysis of projects, including supply chain emissions. It was applied to the Glasgow 2014 Commonwealth Games Athletes' Village remediation project, for which a calculated total ‘carbon footprint’ of 2328 t of carbon dioxide equivalent emission (tCO2e) was obtained. This is 71 tCO2e/ha of the site or 13·3 kgCO2e/t whole life of soil treated. These figures are not comparable with those reported for other projects, which have typically not included supply chain emissions. Fuel use was the main contributor to emissions, but the contribution made by staff transport and carbon dioxide embodied in construction plant was also found to be significant. A comparison was made with an excavate and disposal (E&D) approach, which required considerable use of estimation for the hypothetical E&D. However, it was determined that the carbon footprint of E&D may have been 14% higher than the soil washing actually used. It was concluded that fuel efficiency would be key to future reduction of the carbon footprint of remediation projects, that the accounting tool would be useful for ongoing project management, and its application over time could lead to a database of values for optioneering at the process design stage

Improving the care of people with dementia in general hospitals: evaluation of a whole-system train the trainer model

Background: There are concerns about the quality of care that people with dementia receive in the general hospital. Staff report a lack of confidence and inadequate training in dementia care. Methods: A train-the-trainer model was implemented across eight acute hospital trusts in London via a large academic health and science network. Impact was evaluated using mixed methods. Data was collected at (a) Individual level: ‘Sense of Competence in Dementia Care’ (SCID) (b) Ward level: Person Interaction and Environment (PIE) observations (c) Organisation level: use of specific tools i.e. “This Is Me”, (d) Systems level: numbers and types of staff trained per trust. Results were analysed with descriptive statistics and paired t-test with thematic framework analysis for PIE observations. Results: Number of staff trained per trust ranged from 67 to 650 (total 2,020). 1,688 (85%) baseline questionnaires and 456 (27%) 3 month follow-up questionnaires were completed. Mean SCID score was 43.2 at baseline and 50.7 at follow-up (paired t-test, p<0.001). All sub-scales showed a small increase in competence, the largest being for ‘building relationships’. Organisational level data suggested increased use of carer’s passport, “This Is Me” documentation, dementia information leaflets, delirium screening scales and pathways. PIE observations demonstrated improved staff-patient interactions but little change in hospital environments. Conclusions: There was a significant improvement in staffs’ sense of competence in dementia care and the quality of interactions with patients. More hospitals adopted person centred tools and pathways. Work is required to investigate if these changes improve hospital outcomes for people with dementia

Imaging of Convection Enhanced Delivery of Toxins in Humans

Drug delivery of immunotoxins to brain tumors circumventing the blood brain barrier is a significant challenge. Convection-enhanced delivery (CED) circumvents the blood brain barrier through direct intracerebral application using a hydrostatic pressure gradient to percolate therapeutic compounds throughout the interstitial spaces of infiltrated brain and tumors. The efficacy of CED is determined through the distribution of the therapeutic agent to the targeted region. The vast majority of patients fail to receive a significant amount of coverage of the area at risk for tumor recurrence. Understanding this challenge, it is surprising that so little work has been done to monitor the delivery of therapeutic agents using this novel approach. Here we present a review of imaging in convection enhanced delivery monitoring of toxins in humans, and discuss future challenges in the field

Discovery of the Cobalt Isotopes

Twenty-six cobalt isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.Comment: to be published in Atomic Data and Nuclear Data Table

How do people living with dementia perceive eating and drinking difficulties? A qualitative study

BACKGROUND: Eating and drinking problems are common among people living with later-stage dementia, yet few studies have explored their perspectives. OBJECTIVE: This study aimed to explore how people living with mild dementia understand possible future eating and drinking problems and their perspectives on assistance. DESIGN: Qualitative study using semi-structured interviews. SETTING: Community. METHODS: We conducted semi-structured interviews with 19 people living with mild dementia. Interviews were transcribed verbatim and analysed thematically. RESULTS: Five themes were identified: (i) awareness of eating and drinking problems; (ii) food and drink representing an individual’s identity and agency; (iii) delegating later decisions about eating and drinking to family carers; (iv) acceptability of eating and drinking options; and (v) eating and drinking towards the end of life. For people living with mild dementia, possible later eating and drinking problems could feel irrelevant and action may be postponed until they occur. Fears of being a burden to family and of being treated like a child may explain reluctance to discuss such future problems. People living with mild dementia might wish to preserve their agency and maintain good quality of life, rather than be kept alive at later stages by artificial nutrition and hydration. CONCLUSION: For people with mild dementia, eating and drinking problems may seem unrelated to them and so get left undiscussed. Negative connotations regarding eating and drinking problems may hinder the discussion. The optimal time to discuss possible future problems with eating and drinking with people with mild dementia may need an individual approach

Experiences of Carers and People with Dementia from Ethnic Minority Groups Managing Eating and Drinking at Home in the United Kingdom

Eating and drinking difficulties, such as loss of appetite and swallowing problems, are common in dementia, but little is known about the experiences of ethnic minority groups who are managing these difficulties at home. The purpose of our study was to explore the meaning of food, the impact of dementia on eating and drinking, and carers’ experiences of support. We undertook semi-structured interviews with 17 carers and people with dementia from ethnic minority backgrounds living in England, using thematic analysis to analyse the data. Food/drink had strong links to identity, culture and emotions. Providing culturally familiar foods, celebrating traditional festivals and supporting previous food-related roles promoted reminiscence, which encouraged the people living with dementia to eat and drink, as did social interactions, although these could lead to distress in those with more advanced dementia. Food choices were also influenced by carer strain, generational differences and the impact of health conditions. Despite a strong sense of duty to care for relatives at home, there was low awareness of community support services. The carers expressed a need for culturally tailored support for managing dementia-related eating and drinking difficulties at home. Healthcare professionals must provide contextually relevant advice to carers, being mindful of how cultural backgrounds can affect dietary choices

Family caregivers’ and professionals’ experiences of supporting people living with dementia’s nutrition and hydration needs towards the end-of-life

The aim of this paper was to understand the needs of family caregivers and professionals supporting people living with dementia with eating and drinking difficulties towards the end of life and the strategies they use to overcome them. A total of 41 semi-structured interviews with family caregivers (n = 21) and professionals (n = 20) were conducted in London and surrounding areas of England. Interviews were audio-recorded and transcribed verbatim. Four themes were identified: caregivers accessing and seeking help, perceived priorities of care, professionals' supportiveness and educational role, and strategies. Caregivers often struggle as they are not aware of the eating and drinking difficulties associated with dementia's progression. Care can change over time with families prioritising a person's comfort towards the end of life rather than ensuring a particular level of nutrition. Mutual support is required by both professionals and caregivers to enhance the care of the person living with dementia. Cognitive difficulties are often behind initial eating and drinking challenges in dementia, whereas physical challenges take over towards the later stages. Flexibility and creativity are key to adapting to changing needs. There is a need to raise awareness of the eating and drinking challenges associated with the progression of dementia. Professionals can help caregivers embark on the transition towards focussing on comfort and enjoyment of eating and drinking near the end of life rather than nutrition. This is particularly relevant for those caring for a relative living at home. Caregivers' input is needed to tailor professionals' recommendations