Didier G Leibovici

Dr. Didier G Leibovici

School of Mathematics & Statistics, University of Sheffield, UK

Research Focus & Metrics

Academic Career Length

32Years (1995-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 January 2017 in Natural Hazards
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JRJulian Rosser
Julian Rosser
Didier G LeiboviciDidier G Leibovici
Didier G Leibovici
MJMichael John Jackson
Michael John Jackson
Flood events cause substantial damage to urban and rural areas. Monitoring water extent during large-scale flooding is crucial in order to identify the area affected and to evaluate damage. During such events, spatial assessments of floodwater may be derived from satellite or airborne sensing platforms. Meanwhile, an increasing availability of smartphones is leading to documentation of flood events directly by individuals, with information shared in real-time using social media. Topographic data, which can be used to determine where floodwater can accumulate, are now often available from national mapping or governmental repositories. In this work, we present and evaluate a method for rapidly estimating flood inundation extent based on a model that fuses remote sensing, social media and topographic data sources. Using geotagged photographs sourced from social media, optical remote sensing and high-resolution terrain mapping, we develop a Bayesian statistical model to estimate the probability of flood inundation through weights-of-evidence analysis. Our experiments were conducted using data collected during the 2014 UK flood event and focus on the Oxford city and surrounding areas. Using the proposed technique, predictions of inundation were evaluated against ground-truth flood extent. The results report on the quantitative accuracy of the multisource mapping process, which obtained area under receiver operating curve values of 0.95 and 0.93 for model fitting and testing, respectively.

13 March 2015 in Public Health Nutrition
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ACAngie Clonan
Angie Clonan
PWPaul Wilson
Paul Wilson
JSJudy A Swift
Judy A Swift
Didier G LeiboviciDidier G Leibovici
Didier G Leibovici
MHMichelle Holdsworth
Michelle Holdsworth
Objective: Higher intakes of red and processed meat are associated with poorer health outcomes and negative environmental impacts. Drawing upon a population survey the present paper investigates meat consumption behaviours, exploring perceived impacts for human health, animal welfare and the environment.Design: Structured self-completion postal survey relating to red and processed meat, capturing data on attitudes, sustainable meat purchasing behaviour, red and processed meat intake, plus sociodemographic characteristics of respondents.Setting: Urban and rural districts of Nottinghamshire, East Midlands, UK, drawn from the electoral register.Subjects: UK adults (n 842) aged 18–91 years, 497 females and 345 males, representing a 35·6 % response rate from 2500 randomly selected residents.Results: Women were significantly more likely (P60 years) were more likely to hold positive attitudes towards animal welfare (P<0·01). Less than a fifth (18·4 %) of the sample agreed that the impact of climate change could be reduced by consuming less meat, dairy products and eggs. Positive attitudes towards animal welfare were associated with consuming less meat and a greater frequency of ‘higher welfare’ meat purchases.Conclusions: Human health and animal welfare are more common motivations to avoid red and processed meat than environmental sustainability. Policy makers, nutritionists and health professionals need to increase the public’s awareness of the environmental impact of eating red and processed meat. A first step could be to ensure that dietary guidelines integrate the nutritional, animal welfare and environmental components of sustainable diets.

1 February 1999 in International Journal of Epidemiology
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Didier G LeiboviciDidier G Leibovici
Didier G Leibovici
KRK Ritchie
K Ritchie
BLB Ledésert
B Ledésert
JTJ Touchon
J Touchon
BACKGROUND: Evidence relating to the potentially protective effect of smoking and alcohol consumption in relation to senescent cognitive decline and Alzheimer's disease is inconclusive. METHODS: The relationship between wine and tobacco consumption and cognitive change was assessed within a longitudinal study of normal elderly people showing recent instability in cognitive functioning using an extensive battery of cognitive tests. RESULTS: While moderate wine consumption was found to be associated with a fourfold diminishing of the risk of Alzheimer's disease (OR = 0.26), as found in other studies, this effect was found to disappear when institutionalization was taken into account. Wine consumption was associated with an increased risk of decline over time in attention and in secondary memory. No protective effect for Alzheimer's disease was found for smoking, although smoking was associated with a decreased risk for decline over time in attentional and visuospatial functioning. No clear combined effect of smoking and drinking was found, even though smoking was found to increase the risk of decline in language performance when adjusted on wine consumption. CONCLUSIONS: There is no evidence to suggest that wine and tobacco consumption may protect against Alzheimer's disease.

20 January 2014 in International Journal of Geographical Information Science
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Didier G LeiboviciDidier G Leibovici
Didier G Leibovici
Christophe ClaramuntChristophe Claramunt
Christophe Claramunt
DGDamien Le Guyader
Damien Le Guyader
DBDavid Brosset
David Brosset
Http://www.tandfonline.com/eprint/p4CaesjPNyeeSiHGCxpX/fullInternational audienceWhen it comes to characterize the distribution of 'things' observed spatially and identified by their geometries and attributes, the Shannon entropy has been widely used in different domains such as ecology, regional sciences, epidemiology and image analysis. In particular, recent research has taken into account the spatial patterns derived from topological and metric properties in order to propose extensions to the measure of entropy. Based on two different approaches using either distance-ratios or co-occurrences of observed classes, the research developed in this paper introduces several new indices and explores their extensions to the spatio-temporal domains which are derived whilst investigating further their application as global and local indices. Using a multiplicative space-time integration approach either at a macro or micro-level, the approach leads to a series of spatio-temporal entropy indices including from combining co-occurrence and distances-ratios approaches. The framework developed is complementary to the spatio-temporal clustering problem, introducing a more spatial and spatio-temporal structuring perspective using several indices characterizing the distribution of several class instances in space and time. The whole approach is first illustrated on simulated data evolutions of three classes over seven time stamps. Preliminary results are discussed for a study of conflicting maritime activities in the Bay of Brest where the objective is to explore the spatio-temporal patterns exhibited by a categorical variable with six classes, each representing a conflict between two maritime activities

1 June 2001 in NeuroImage
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SSStephen Smith
Stephen Smith
PBPeter R. Bannister
Peter R. Bannister
CBChristian Beckmann
Christian Beckmann
MBMike Brady
Mike Brady
SCStuart Clare
Stuart Clare
YZYongyue Zhang
Yongyue Zhang

24 May 2011 in Public Health Nutrition
Verified
Journal Article
Open access
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ACAngie Clonan
Angie Clonan
MHMichelle Holdsworth
Michelle Holdsworth
JSJudy A Swift
Judy A Swift
Didier G LeiboviciDidier G Leibovici
Didier G Leibovici
PWPaul Wilson
Paul Wilson
Objective: Despite widespread concern over exploitation of the European Union's fish stocks, dietary guidelines in the UK continue to recommend two portions of fish per week. The present study sought to investigate whether health and/or sustainability are motivating factors when purchasing and consuming fish and whether there are sociodemographic trends.Design: A structured, self-completion postal questionnaire exploring consumers’ attitudes towards purchasing fish, their dietary intake, stated purchasing behaviour and sociodemographic information.Setting: Nottinghamshire, UK.Subjects: Adults from 842 households randomly selected from the electoral register.Results: Over half of the participants (57·0 %) were aware of the health benefits of fish consumption and reported health as a primary motivator for purchasing fish; however, only 26·8 % actively sought to purchase fish from a sustainable source (e.g. Marine Stewardship Council (MSC) certified fish). Only 30·6 % of participants met current dietary recommendations for fish intake. Older respondents (>60 years of age) were more likely to report purchasing fish for health reasons and to buy MSC fish. Participants were significantly less likely to report MSC purchases if they agreed with the statement ‘I am confused about which type of fish I should be eating to protect fish stocks’ (P< 0·001).Conclusions: The number of consumers purchasing fish for health reasons was more than those seeking sustainably sourced fish; yet, they still failed to meet the recommended intake set by the Food Standards Agency. Dietary advice to the public to increase consumption of fish conflicts with the prevailing pressure on fish stocks. Clear advice should be communicated enabling consumers to meet nutritional needs while protecting fish stocks.