HyperImage – Image-Oriented e-Science Networks

Images are an important source of scientific knowledge in many disciplines. E.g. you want to analyse satellite photographs or x-ray images of human livers or symbols of death in Dutch baroque paintings. You study the relevant images closely and compare details of one image with details of another. When you want to share your knowledge you will necessarily also communicate about image details. Using paper images, you can just mark up details of interest with a pencil. But with digital images you either have to make marks by employing an image manipulation software, which is not as widespread and easy to use as current text processing software is. Or you have to describe your findings verbally, such as "... above left is an interesting dark spot in picture No. 1 ... now compare it to picture No. 2 where a similar dark spot can be found nearly in the centre of the picture ..." and so on. Neither the employment of a complex image manipulation software package nor the time consuming and not very precise verbal description is satisfactory and appropriate for everyday use in science. Additionally, any technical solution to the lack of easy-to-use technology has to be Web-based in order to support collaborative research on images. The HyperImage project is concerned with the currently unsolved technical problem of establishing links between image details. Our goal is to develop a Web-based workspace that will enable scientists in any image-oriented discipline to create simple and precise links between images and image details, in a fashion similar to that which until now has been the privilege of text. The HyperImage editor permits scientists to mark details of pictures and create links between images and image details of any scale. It is programmed as a platform independent Java application and is open source (GNU Lesser General Public Licence). Any work in progress can be stored within the Hyper- Image system by an author or group of authors, or it can be exported as XML for further usage outside the HyperImage system. Currently we are testing our software prototype with our HyperImage partners from the faculties of Art History and Biology

Photoemission spectroscopy and sum rules in dilute electron-phonon systems

A family of exact sum rules for the one-polaron spectral function in the low-density limit is derived. An algorithm to calculate energy moments of arbitrary order of the spectral function is presented. Explicit expressions are given for the first two moments of a model with general electron-phonon interaction, and for the first four moments of the Holstein polaron. The sum rules are linked to experiments on momentum-resolved photoemission spectroscopy. The bare electronic dispersion and the electron-phonon coupling constant can be extracted from the first and second moments of spectrum. The sum rules could serve as constraints in analytical and numerical studies of electron-phonon models.Comment: 4 page

Phonon Coherence and New Set of Sidebands in Phonon-Assisted Photoluminescence

We investigate excitonic polaron states comprising a local exciton and phonons in the longitudinal optical (LO) mode by solving the Schr\"{o}dinger equation. We derive an exact expression for the ground state (GS), which includes multi-phonon components with coefficients satisfying the Huang-Rhys factors. The recombination of GS and excited polaron states gives one set of sidebands in photoluminescence (PL): the multi-phonon components in the GS produce the Stokes lines and the zero-phonon components in the excited states produce the anti-Stokes lines. By introducing the mixing of the LO mode and environal phonon modes, the exciton will also couple with the latter, and the resultant polaron states result in another set of phonon sidebands. This set has a zero-phonon line higher and wider than that of the first set due to the tremendous number of the environal modes. The energy spacing between the zero-phonon lines of the first and second sets is proved to be the binding energy of the GS state. The common exciton origin of these two sets can be further verified by a characteristic Fano lineshape induced by the coherence in the mixing of the LO and the environal modes.Comment: 5 pages, 3 figures 1 figure (fig. 1) replaced 1 figure (fig. 2) remove

Instability due to long range Coulomb interaction in a liquid of polarizable particles (polarons, etc.)

The interaction Hamiltonian for a system of polarons a la Feynman in the presence of long range Coulomb interaction is derived and the dielectric function is computed in mean field. For large enough concentration a liquid of such particles becomes unstable. The onset of the instability is signaled by the softening of a collective optical mode in which all electrons oscillate in phase in their respective self-trapping potential. We associate the instability with a metallization of the system. Optical experiments in slightly doped cuprates and doped nickelates are analyzed within this theory. We discuss why doped cuprates matallize whereas nickelates do not.Comment: 5 pages,1 figur

Les stratégies d'équipement en stations de pompage des petites exploitations agricoles du Tadla

International audienceA la suite de plusieurs épisodes de sécheresses et de la libéralisation des assolements au Maroc, les deux dernières décennies ont vu le développement massif de stations de pompage dans les périmètres irrigués du Tadla (la dotation est de 131 millions de m3 dans le périmètre du Béni Amir en 2001-2002, pratiquement la moitié de la période 1978-2002). De plus, la libéralisation des assolements a induit une baisse des cultures industrielles et une diversification entraînant une demande en eau plus complexe à satisfaire. Actuellement, d'après les estimations, plus de 10 000 puits et forages sont fonctionnels dans ces périmètres de grande hydraulique. Ces stations de pompage, qui appartiennent souvent à des exploitations familiales ou à des petites associations d'exploitations liées par parenté ou voisinage, peuvent prélever chacune jusqu'à 100 000 m3/an. On estime qu'environ 50 % des exploitations n'ont pas accès à l'eau souterraine. A travers une étude d'une quinzaine d'exploitations agricoles sur un canal tertiaire dans le périmètre des Béni Amir dans le Tadla, nous cherchons à comprendre les stratégies d'équipement en station de pompage et à étudier leur impact sur l'intensification des assolements et sur l'évolution des résultats économiques des exploitations agricoles. Le modèle de simulation Olympe (simulateur d'aide à la décision pour l'orientation stratégique de l'exploitation agricole) est exploité pour constituer une base de données sur les systèmes de production des exploitations et comme outil de simulation pour l'orientation stratégique de l'exploitation agricole, à l'échelle individuelle. Ainsi, les simulations montrent l'intérêt de l'équipement en station de pompage en fonction de la taille de l'exploitation. En conclusion, les échanges d'eau souterraine pourraient constituer une opportunité pour davantage utiliser le parc existant de stations de pompage (les taux d'utilisation des forages sont inférieurs à 21 %) et améliorer les bilans financiers des exploitations

Evaluation of the feasibility and acceptability of the 'Care for Stroke' intervention in India, a smartphone-enabled, carer-supported, educational intervention for management of disability following stroke.

OBJECTIVES: (1) To identify operational issues encountered by study participants in using the 'Care for Stroke' intervention; (2) to evaluate the feasibility and acceptability of the intervention. DESIGN: Mixed-methods research design. SETTING: Participant's home. Participants were selected from a tertiary hospital in Chennai, South India. PARTICIPANTS: Sixty stroke survivors treated and discharged from the hospital, and their caregivers. INTERVENTION: 'Care for Stroke' is a smartphone-enabled, educational intervention for management of physical disabilities following stroke. It is delivered through a web-based, smartphone-enabled application. It includes inputs from stroke rehabilitation experts in a digitised format. METHODS: Evaluation of the intervention was completed in two phases. In the first phase, the preliminary intervention was field-tested with 30 stroke survivors for 2 weeks. In the second phase, the finalised intervention was provided to a further 30 stroke survivors to be used in their homes with support from their carers for 4 weeks. PRIMARY AND SECONDARY OUTCOME MEASURES: PRIMARY OUTCOMES: (1) operational difficulties in using the intervention; (2) feasibility and acceptability of the intervention in an Indian setting. Disability and dependency were assessed as secondary outcomes. RESULTS: Field-testing identified operational difficulties related to connectivity, video-streaming, picture clarity, quality of videos, and functionality of the application. The intervention was reviewed, revised and finalised before pilot-testing. Findings from the pilot-testing showed that the 'Care for Stroke' intervention was feasible and acceptable. Over 90% (n=27) of the study participants felt that the intervention was relevant, comprehensible and useful. Over 96% (n=29) of the stroke survivors and all the caregivers (100%, n=30) rated the intervention as excellent and very useful. These findings were supported by qualitative interviews. CONCLUSIONS: Evaluation indicated that the 'Care for Stroke' intervention was feasible and acceptable in an Indian context. An assessment of effectiveness is now warranted

De l'eau aux dattes : aperçu de la filière datte tunisienne et perspectives d'interventions

La modernisation et l'extension des aménagements hydrauliques dans les oasis du Sud tunisien renchérissent le coût de l'eau tout en accentuant la pression sur la ressource. Or ces oasis sont majoritairement orientées vers la production d'une variété de datte destinée principalement au marché international, la Deglet el Nour. La valorisation de l'eau par ces systèmes de production, et plus généralement, leur durabilité économique et écologique sont donc dépendantes du fonctionnement et des performances de la filière datte, particulièrement dans sa composante exportatrice. Partant des nombreuses études réalisées, complétées par un ensemble d'interviews réalisé dans le cadre du projet Sirma, cet article présente un aperçu de l'organisation et du fonctionnement de la filière. Celle-ci comprend 3 grands types d'acteurs : des producteurs nombreux, de petite taille et atomisés, des conditionneurs-exportateurs peu nombreux mais intégrant faiblement l'amont et l'aval, et des collecteurs jouant le rôle d'intermédiaires entre les précédents. La filière fonctionne essentiellement sous la forme d'un marché spot, sans réelle maîtrise des quantités et qualités livrées. Des stratégies d'investissement dans des capacités de stockage apparaissent néanmoins avec le décalage à venir entre la période de récolte (octobre à décembre) et le ramadan, pic de consommation. Quelques perspectives d'intervention sont tirées de ce premier diagnostic, replacées dans une problématique plus générale de supply chain management

[Accepted Manuscript] Field testing a draft version of the UNICEF/Washington Group Module on child functioning and disability. Background, methodology and preliminary findings from Cameroon and India

Background Global child disability data are generally non-comparable, comprising different tools, methodologies and disability definitions. UNICEF and The Washington Group on Disability Statistics (WG) have developed a new tool on child functioning and disability to address this need. Aims The aim of this paper is to describe the development of the new module, and to present an independent field test of the draft module in two contrasting settings. Methods UNICEF and the WG developed a parent-reported survey module to identify children aged 2�17 years with functional difficulties in population-based surveys through: review of existing documentation, consultation with experts and cognitive testing. A field test of the draft module was undertaken in Cameroon and India within a population-based survey. Functional limitation in each of 14 domains was scored on a scale comprising �no difficulty�, �some difficulty�, �a lot of difficulty� and �cannot do�. Results In all, 1713 children in Cameroon and 1101 children in India were assessed. Sixty-four percent of children in Cameroon and 35% of children in India were reported to have at least some difficulty in one or more domain. The proportion reported to have either �a lot of difficulty� or �cannot do� was 9% in Cameroon and 4% in India. There were no significant differences in reported functional difficulties by sex but children aged 2�4 were reported to have fewer functional difficulties of any kind compared with older children in both countries. Conclusion Comparable estimates were generated between the two countries, providing an initial overview of the tool's outputs. The continued development of this standardised questionnaire for the collection of robust and reliable data on child disability is essential