Structured sparsity for spatially coherent fibre orientation estimation in diffusion MRI.

We propose a novel formulation to solve the problem of intra-voxel reconstruction of the fibre orientation distribution function (FOD) in each voxel of the white matter of the brain from diffusion MRI data. The majority of the state-of-the-art methods in the field perform the reconstruction on a voxel-by-voxel level, promoting sparsity of the orientation distribution. Recent methods have proposed a global denoising of the diffusion data using spatial information prior to reconstruction, while others promote spatial regularisation through an additional empirical prior on the diffusion image at each q-space point. Our approach reconciles voxelwise sparsity and spatial regularisation and defines a spatially structured FOD sparsity prior, where the structure originates from the spatial coherence of the fibre orientation between neighbour voxels. The method is shown, through both simulated and real data, to enable accurate FOD reconstruction from a much lower number of q-space samples than the state of the art, typically 15 samples, even for quite adverse noise conditions.

Evolutionary dynamics of collective action in spatially structured populations.

Many models proposed to study the evolution of collective action rely on a formalism that represents social interactions as n-player games between individuals adopting discrete actions such as cooperate and defect. Despite the importance of spatial structure in biological collective action, the analysis of n-player games games in spatially structured populations has so far proved elusive. We address this problem by considering mixed strategies and by integrating discrete-action n-player games into the direct fitness approach of social evolution theory. This allows to conveniently identify convergence stable strategies and to capture the effect of population structure by a single structure coefficient, namely, the pairwise (scaled) relatedness among interacting individuals. As an application, we use our mathematical framework to investigate collective action problems associated with the provision of three different kinds of collective goods, paradigmatic of a vast array of helping traits in nature: "public goods" (both providers and shirkers can use the good, e.g., alarm calls), "club goods" (only providers can use the good, e.g., participation in collective hunting), and "charity goods" (only shirkers can use the good, e.g., altruistic sacrifice). We show that relatedness promotes the evolution of collective action in different ways depending on the kind of collective good and its economies of scale. Our findings highlight the importance of explicitly accounting for relatedness, the kind of collective good, and the economies of scale in theoretical and empirical studies of the evolution of collective action.

Managing the Sick Child in the Era of Declining Malaria Transmission: Development of ALMANACH, an Electronic Algorithm for Appropriate Use of Antimicrobials.

OBJECTIVE: To review the available knowledge on epidemiology and diagnoses of acute infections in children aged 2 to 59 months in primary care setting and develop an electronic algorithm for the Integrated Management of Childhood Illness to reach optimal clinical outcome and rational use of medicines. METHODS: A structured literature review in Medline, Embase and the Cochrane Database of Systematic Review (CDRS) looked for available estimations of diseases prevalence in outpatients aged 2-59 months, and for available evidence on i) accuracy of clinical predictors, and ii) performance of point-of-care tests for targeted diseases. A new algorithm for the management of childhood illness (ALMANACH) was designed based on evidence retrieved and results of a study on etiologies of fever in Tanzanian children outpatients. FINDINGS: The major changes in ALMANACH compared to IMCI (2008 version) are the following: i) assessment of 10 danger signs, ii) classification of non-severe children into febrile and non-febrile illness, the latter receiving no antibiotics, iii) classification of pneumonia based on a respiratory rate threshold of 50 assessed twice for febrile children 12-59 months; iv) malaria rapid diagnostic test performed for all febrile children. In the absence of identified source of fever at the end of the assessment, v) urine dipstick performed for febrile children <2 years to consider urinary tract infection, vi) classification of 'possible typhoid' for febrile children >2 years with abdominal tenderness; and lastly vii) classification of 'likely viral infection' in case of negative results. CONCLUSION: This smartphone-run algorithm based on new evidence and two point-of-care tests should improve the quality of care of <5 year children and lead to more rational use of antimicrobials.

Bias in dissemination of clinical research findings: structured OPEN framework of what, who and why, based on literature review and expert consensus.

OBJECTIVE: The aim of this study is to review highly cited articles that focus on non-publication of studies, and to develop a consistent and comprehensive approach to defining (non-) dissemination of research findings. SETTING: We performed a scoping review of definitions of the term 'publication bias' in highly cited publications. PARTICIPANTS: Ideas and experiences of a core group of authors were collected in a draft document, which was complemented by the findings from our literature search. INTERVENTIONS: The draft document including findings from the literature search was circulated to an international group of experts and revised until no additional ideas emerged and consensus was reached. PRIMARY OUTCOMES: We propose a new approach to the comprehensive conceptualisation of (non-) dissemination of research. SECONDARY OUTCOMES: Our 'What, Who and Why?' approach includes issues that need to be considered when disseminating research findings (What?), the different players who should assume responsibility during the various stages of conducting a clinical trial and disseminating clinical trial documents (Who?), and motivations that might lead the various players to disseminate findings selectively, thereby introducing bias in the dissemination process (Why?). CONCLUSIONS: Our comprehensive framework of (non-) dissemination of research findings, based on the results of a scoping literature search and expert consensus will facilitate the development of future policies and guidelines regarding the multifaceted issue of selective publication, historically referred to as 'publication bias'.

L-Fuzzy Structured Query Language

Lattice valued fuzziness is more general than crispness or fuzziness based on the unit interval. In this work, we present a query language for a lattice based fuzzy database. We define a Lattice Fuzzy Structured Query Language (LFSQL) taking its membership values from an arbitrary lattice L. LFSQL can handle, manage and represent crisp values, linear ordered membership degrees and also allows membership degrees from lattices with non-comparable values. This gives richer membership degrees, and hence makes LFSQL more flexible than FSQL or SQL. In order to handle vagueness or imprecise information, every entry into an L-fuzzy database is an L-fuzzy set instead of crisp values. All of this makes LFSQL an ideal query language to handle imprecise data where some factors are non-comparable. After defining the syntax of the language formally, we provide its semantics using L-fuzzy sets and relations. The semantics can be used in future work to investigate concepts such as functional dependencies. Last but not least, we present a parser for LFSQL implemented in Haskell.

Writing a Technical Report for Electronic and Electrical Engineers

Has a mixture of factual information (conventions on how a report should be structured) and motivational information on improving writing and communication skills

Document engineering approaches toward scalable and structured multimedia, web and printable documents

Document engineering is the computer science discipline that investigates systems for documents in any form and in all media. As with the relationship between software engineering and software, document engineering is concerned with principles, tools and processes that improve our ability to create, manage, and maintain documents (http://www.documentengineering.org). The ACM Symposium on Document Engineering is an annual meeting of researchers active in document engineering: it is sponsored by ACM by means of the ACM SIGWEB Special Interest Group. In this editorial, we first point to work carried out in the context of document engineering, which are directly related to multimedia tools and applications. We conclude with a summary of the papers presented in this special issue.

Microstructural and electric properties of bismuth-layered structured ceramics - SrBi2(Ta1-xNbx)O-9

Ceramic samples of SrBi2(Nb1-xTax)O-9 (0 less than or equal to x less than or equal to 1) were prepared by the solid state reaction method in order to investigate their structural and electrical features as well as obtain useful information to improve the properties of SrBi2(Nb1-xTax)O-9 as a thin film. The X-ray diffraction patterns and the scanning electronic microscopy photomicrographs show no secondary phases but the formation of a solid-state solution for all the composition. The ac conductivity of the samples, measured at 25 degreesC and 100 kHz frequency, decreases with the increase of Ta content. Such results were explained by intrinsic conductivity of pure components.

Mechanically activating formation of layered structured bismuth titanate

Bismuth titanatc-Bi(4)Ti(3)O(12) (BIT) with wide application in the electronic industry as capacitors, memory devices and sensors is the simplest compound in the Aurivillius family, which consists of (Bi(2)O(2))(2+) sheets alternating with (Bi(2)T(i)3O(10))(2-) perovskite-like layers. The synthesis of more resistive BIT ceramics would be preferable advance in obtaining of well-densified ceramic with small grains randomly oriented to limit the conductivity along the (Bi(2)O(2))(2+) layers. Having in mind that the conventional ceramic route for the synthesis can lead to non-stoichiometry in composition, in consequence of the undesirable loss in bismuth content through volatilization of Bi(2)O(3) at elevated temperature, our efforts were addressed to preparation of BIT by mechanical activation the constituent oxides. The nucleation and phase formation of BIT, crystal structure, microstructure, powder particle size and specific surface area were followed by XRD, Rietveld refinement analysis, thermal analysis, scanning electron microscopy (SEM) and the BET specific surface area measurements. (c) 2005 Elsevier B.V. All rights reserved.

Interface formation of nanostructured heterojunction SnO 2:Eu/GaAs and electronic transport properties

Thin films of tin dioxide (SnO2) are deposited by the sol-gel-dip-coating technique, along with GaAs layers, deposited by the resistive evaporation technique. The as-built heterojunction has potential application in optoelectronic devices, combining the emission from the rare-earth doped transparent oxide (Eu3+-doped SnO2 presents very efficient red emission) with a high mobility semiconductor. The advantage of this structure is the possibility of separation of the rare-earth emission centers from the electron scattering, leading to a strongly indicated combination for electroluminescence. Electrical characterization of the heterojunction SnO2:Eu/GaAs shows a significant conductivity increase when compared to the conductivity of the individual films, and the monochromatic light irradiation (266 nm) at low temperature of the heterojunction GaAs/SnO2:Eu leads to intense conductivity increase. Scanning electron microscopy (SEM) of the heterojunction cross section shows high adherence and good morphological quality of the interfaces substrate/SnO2 and SnO2/GaAs, even though the atomic force microscopy (AFM) image of the GaAs surface shows disordered particles, which increases with sample thickness. On the other hand, the good morphology of the SnO2:Eu surface, shown by AFM, assures the good electrical performance of the heterojunction. The observed improvement on the electrical transport properties is probably related to the formation of short conduction channels at the semiconductors interface, which may exhibit two-dimensional electron gas (2DEG) behavior. © 2012 Elsevier B.V. All rights reserved.

Nanomechanical and phononic properties of structured soft materials

Significant interest in nanotechnology, is stimulated by the fact that materials exhibit qualitative changes of properties when their dimensions approach ”finite-sizes”. Quantization of electronic, optical and acoustic energies at the nanoscale provides novel functions, with interests spanning from electronics and photonics to biology. The present dissertation involves the application of Brillouin light scattering (BLS) to quantify and utilize material displacementsrnfor probing phononics and elastic properties of structured systems with dimensions comparable to the wavelength of visible light. The interplay of wave propagation with materials exhibiting spatial inhomogeneities at sub-micron length scales provides information not only about elastic properties but also about structural organization at those length scales. In addition the vector nature of q allows, for addressing the directional dependence of thermomechanical properties. To meet this goal, one-dimensional confined nanostructures and a biological system possessing high hierarchical organization were investigated. These applications extend the capabilities of BLS from a characterization tool for thin films to a method for unravelingrnintriguing phononic properties in more complex systems.

Feasibility and acceptance of electronic quality of life assessment in general practice: an implementation study

Background Patients' health related quality of life (HRQoL) has rarely been systematically monitored in general practice. Electronic tools and practice training might facilitate the routine application of HRQoL questionnaires. Thorough piloting of innovative procedures is strongly recommended before the conduction of large-scale studies. Therefore, we aimed to assess i) the feasibility and acceptance of HRQoL assessment using tablet computers in general practice, ii) the perceived practical utility of HRQoL results and iii) to identify possible barriers hindering wider application of this approach. Methods Two HRQoL questionnaires (St. George's Respiratory Questionnaire SGRQ and EORTC QLQ-C30) were electronically presented on portable tablet computers. Wireless network (WLAN) integration into practice computer systems of 14 German general practices with varying infrastructure allowed automatic data exchange and the generation of a printout or a PDF file. General practitioners (GPs) and practice assistants were trained in a 1-hour course, after which they could invite patients with chronic diseases to fill in the electronic questionnaire during their waiting time. We surveyed patients, practice assistants and GPs regarding their acceptance of this tool in semi-structured telephone interviews. The number of assessments, HRQoL results and interview responses were analysed using quantitative and qualitative methods. Results Over the course of 1 year, 523 patients filled in the electronic questionnaires (1–5 times; 664 total assessments). On average, results showed specific HRQoL impairments, e.g. with respect to fatigue, pain and sleep disturbances. The number of electronic assessments varied substantially between practices. A total of 280 patients, 27 practice assistants and 17 GPs participated in the telephone interviews. Almost all GPs (16/17 = 94%; 95% CI = 73–99%), most practice assistants (19/27 = 70%; 95% CI = 50–86%) and the majority of patients (240/280 = 86%; 95% CI = 82–91%) indicated that they would welcome the use of electronic HRQoL questionnaires in the future. GPs mentioned availability of local health services (e.g. supportive, physiotherapy) (mean: 9.4 ± 1.0 SD; scale: 1 – 10), sufficient extra time (8.9 ± 1.5) and easy interpretation of HRQoL results (8.6 ± 1.6) as the most important prerequisites for their use. They believed HRQoL assessment facilitated both communication and follow up of patients' conditions. Practice assistants emphasised that this process demonstrated an extra commitment to patient centred care; patients viewed it as a tool, which contributed to the physicians' understanding of their personal condition and circumstances. Conclusion This pilot study indicates that electronic HRQoL assessment is technically feasible in general practices. It can provide clinically significant information, which can either be used in the consultation for routine care, or for research purposes. While GPs, practice assistants and patients were generally positive about the electronic procedure, several barriers (e.g. practices' lack of time and routine in HRQoL assessment) need to be overcome to enable broader application of electronic questionnaires in every day medical practice.

Tuberculosis in Cape Town: An age-structured transmission model.

BACKGROUND Tuberculosis (TB) is the leading cause of death in South Africa. The burden of disease varies by age, with peaks in TB notification rates in the HIV-negative population at ages 0-5, 20-24, and 45-49 years. There is little variation between age groups in the rates in the HIV-positive population. The drivers of this age pattern remain unknown. METHODS We developed an age-structured simulation model of Mycobacterium tuberculosis (Mtb) transmission in Cape Town, South Africa. We considered five states of TB progression: susceptible, infected (latent TB), active TB, treated TB, and treatment default. Latently infected individuals could be re-infected; a previous Mtb infection slowed progression to active disease. We further considered three states of HIV progression: HIV negative, HIV positive, on antiretroviral therapy. To parameterize the model, we analysed treatment outcomes from the Cape Town electronic TB register, social mixing patterns from a Cape Town community and used literature estimates for other parameters. To investigate the main drivers behind the age patterns, we conducted sensitivity analyses on all parameters related to the age structure. RESULTS The model replicated the age patterns in HIV-negative TB notification rates of Cape Town in 2009. Simulated TB notification rate in HIV-negative patients was 1000/100,000 person-years (pyrs) in children aged <5 years and decreased to 51/100,000 in children 5-15 years. The peak in early adulthood occurred at 25-29 years (463/100,000 pyrs). After a subsequent decline, simulated TB notification rates gradually increased from the age of 30 years. Sensitivity analyses showed that the dip after the early adult peak was due to the protective effect of latent TB and that retreatment TB was mainly responsible for the rise in TB notification rates from the age of 30 years. CONCLUSION The protective effect of a first latent infection on subsequent infections and the faster progression in previously treated patients are the key determinants of the age-structure of TB notification rates in Cape Town.

Electoral Systems and Ethnic Conciliation: A Structured, Focused Analysis of Vote-Pooling in Northern Ireland Elections 1998-2011

This research project examines the role of electoral system rules in affecting the extent of conciliatory behavior and cross-ethnic coalition making in Northern Ireland. It focuses on the role of the Single Transferable Vote (STV) electoral system in shaping party and voter incentives in a post-conflict divided society. The research uses a structured, focused comparison of the four electoral cycles since the Belfast Agreement of 1998. This enables a systematic examination of each electoral cycle using a common set of criteria focused on conciliation and cross-ethnic coalition making. Whilst preference voting is assumed to benefit moderate candidates, in Northern Ireland centrist and multi-ethnic parties outside of the dominant ethnic communities have received little electoral success. In Northern Ireland the primary effect of STV has not been to encourage inter-communal voting but to facilitate intra-community and intra-party moderation. STV has encouraged the moderation of the historically extreme political parties in each of the ethnic bloc. Patterns across electoral cycles suggest that party elites from the Democratic Unionist Party (DUP) and Sinn Fein have moderated their policy positions due to the electoral system rules. Therefore they have pursued lower-preference votes from within their ethnic bloc but in doing so have marginalized parties of a multi-ethnic or non-ethnic orientation.

Analyzing smooth flowcharts : teaching structured programming in a computer-based education environment /

Vita.