1,081 research outputs found

    MULTIPLE DICTIONARY FOR SPARSE MODELING

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    Much of the progress made in image processing in the past decades can be attributed to better modeling of image content, and a wise deployment of these models in relevant applications. In this paper, we review the role of this recent model in image processing, its rationale, and models related to it. As it turns out, the field of image processing is one of the main beneficiaries from the recent progress made in the theory and practice of sparse and redundant representations. Sparse coding is a key principle that underlies wavelet representation of images. Sparse representation based classification has led to interesting image recognition results, while the dictionary used for sparse coding plays a key role in it. In general, the choice of a proper dictionary can be done using one of two ways: i) building asparsifying  dictionary based on a mathematical model of the data, or ii) learning a dictionary to perform best on a training set

    Desirable BUGS in models of infectious diseases.

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    Bayesian inference using Gibbs sampling (BUGS) is a set of statistical software that uses Markov chain Monte Carlo (MCMC) methods to estimate almost any specified model. Originally developed in the late 1980s, the software is an excellent introduction to applied Bayesian statistics without the need to write a MCMC sampler. The software is typically used for regression-based analyses, but any model that can be specified using graphical nodes are possible. Advanced topics such as missing data, spatial analysis, model comparison and dynamic infectious disease models can be tackled. Three examples are provided; a linear regression model to illustrate parameter estimation, the steps to ensure that the estimates have converged and a comparison of run-times across different computing platforms. The second example describes a model that estimates the probability of being vaccinated from cross-sectional and surveillance data, and illustrates the specification of different models, model comparison and data augmentation. The third example illustrates estimation of parameters within a dynamic Susceptible-Infected-Recovered model. These examples show that BUGS can be used to estimate parameters from models relevant for infectious diseases, and provide an overview of the relative merits of the approach taken

    Antimycobacterial activity of selected medicinal plants extracts from Cameroon

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    New drugs are highly needed to control mycobacterial infections. This study aimed at screening ethnobotanically selected plants extracted using organic solvents for their antimycobacterial activity. In vitro assays were performed on Mycobacterium smegmatis, Mycobacterium avium, Mycobacterium bovis Bacille Calmette Guerin (BCG), Mycobacterium tuberculosis and Mycobacterium ulcerans using the Resazurin Microtiter Assay. Cytotoxicity was assessed on Human lung fibroblast cells (MRC5) and bone marrow-derived macrophages (BMDM) using the MTS tetrazolium assay. The most promising extract from Annickia chlorantha stem bark (ACsbI) was tested for intracellular antimycobacterial activity against M. smegmatis using infected BMDM. Sixty crude extracts, 19 fractions, and 2 purified compounds were obtained from 19 Cameroonian medicinal plants. Results showed that crude extracts mainly inhibited BCG, while interface fractions from A. chlorantha stem bark (ACsbI) and stem (ACstI) displayed the strongest activity against M. ulcerans, with Minimal Inhibitory Concentrations (MIC) of 1.95 and 7.81 µg/ml respectively. Two compounds purified from Sorindeia juglandifolia fruits (SJfr 3.6 and SJfr 4.5) showed activity against BCG and M. ulcerans at 3.9 µg/ml and 62.5 µg/ml respectively. Finally, ACsbI showed no toxicity against MRC5 cells and BMDM and inhibited the growth of intracellular M. smegmatis. The results achieved in this investigation support the traditional to use of these plants and the need to investigate them in deeper details to be able to find alternatives for the existing antimycobacterial drugs

    COVID-19 and mental health of pregnant women in Ceará, Brazil

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    OBJECTIVE To assess the perceptions of pregnant women about COVID-19 and the prevalence of common mental disorders during the implemented social distancing period. METHODS This was an observational, cross-sectional study using digital media, of pregnant women exposed to social distancing due to the COVID-19 pandemic, in Fortaleza, Ceará, Northeastern Brazil. Common mental disorders were estimated using the modified Self-Report Questionnaire-20 (SRQ-20) scale, and the feelings towards COVID-19 were assessed using the Fear of COVID-19 scale through telephone calls made in May 2020. COX multivariate regression models were used to verify the associations. RESULTS Of the 1,041 pregnant women, 45.7% (95%CI: 42.7–48.8) had common mental disorders (CMD). All items of the Fear of COVID-19 Scale showed a significant association with the prevalence of CMD (p < 0.001). A CMD risk gradient was observed, going from a prevalence ratio of 1.52 (95%CI: 1.13–2.04) in pregnant women with two positive items to 2.70 (95%CI: 2.08–3.51) for those with four positive items. Early gestational age and the lack of prenatal care were also associated with CMD. CONCLUSIONS The prevalence of common mental disorders in pregnant women was high during the period of social distancing and was aggravated by negative feelings towards COVID-19

    Palatal rugoscopy as a method of human identification

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    Objetivo: testar a aplicabilidade da fórmula na rugoscopia palatina. Metodologia: três avaliadores examinaram 30 modelos em gesso do arco superior, obtidos de estudantes de Odontologia da UFPB. As rugosidades foram classificadas em simples e compostas e em reta, curva, angular, circular, sinuosa e ponto. Resultados: o exame das rugas simples e compostas, intra avaliador, demonstrou maior percentual de coincidência para as rugas compostas (53,3 a 56,7%), assim como nos exames inter avaliadores, com acertos entre 43,3% e 55,0%, confrontando com os 5,0% e 23,3% obtidos nas rugas simples. Na análise dos tipos fundamentais observa-se que as rugas circulares apresentaram maior percentual de coincidências (95,0% a 96,7%), seguida das angulares (61,7% a 66,7%). A ruga reta demonstrou menor percentual de coincidências (11,7% a 45,0%). As coincidências inter avaliadores foi maior nas rugas circulares (93,3% a 96,7%) e menor nas rugas retas, com percentual entre 16,7% e 15,0%. O maior percentual das rugas compostas demonstra a sua boa visualização. A alta concordância dos avaliadores quanto a rugas circulares ocorre em virtude da classificação de sua ausência, pois raramente se encontra esta ruga, diferente das retas, que se confundem com as sinuosas e vice-versa, frequentemente presentes no palato. Nota-se que a rugosidade palatina como método possui uma grande quantidade de classificações, porém, com praticabilidade baixa, de difícil arquivamento e ausência de padrão universal. Conclusão: a classificação das rugosidades palatinas, por meio da fórmula rugoscópica, não é aplicável devido à subjetividade do método. Palavras-chave: Antropologia Forense; Odontologia Legal; Arcada Dentária

    Engaging stakeholders to level up COPD care in LMICs:lessons learned from the "Breathe Well" programme in Brazil, China, Georgia, and North Macedonia

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    BACKGROUND: Effective stakeholder engagement in health research is increasingly being recognised and promoted as an important pathway to closing the gap between knowledge production and its use in health systems. However, little is known about its process and impacts, particularly in low-and middle-income countries. This opinion piece draws on the stakeholder engagement experiences from a global health research programme on Chronic Obstructive Pulmonary Disease (COPD) led by clinician researchers in Brazil, China, Georgia and North Macedonia, and presents the process, outcomes and lessons learned.MAIN BODY: Each country team was supported with an overarching engagement protocol and mentored to develop a tailored plan. Patient involvement in research was previously limited in all countries, requiring intensive efforts through personal communication, meetings, advisory groups and social media. Accredited training programmes were effective incentives for participation from healthcare providers; and aligning research findings with competing policy priorities enabled interest and dialogue with decision-makers. The COVID-19 pandemic severely limited possibilities for planned engagement, although remote methods were used where possible. Planned and persistent engagement contributed to shared knowledge and commitment to change, including raised patient and public awareness about COPD, improved skills and practice of healthcare providers, increased interest and support from clinical leaders, and dialogue for integrating COPD services into national policy and practice.CONCLUSION: Stakeholder engagement enabled relevant local actors to produce and utilise knowledge for small wins such as improving day-to-day practice and for long-term goals of equitable access to COPD care. For it to be successful and sustained, stakeholder engagement needs to be valued and integrated throughout the research and knowledge generation process, complete with dedicated resources, contextualised and flexible planning, and commitment.</p

    Modelling visual-vestibular integration and behavioural adaptation in the driving simulator

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    It is well established that not only vision but also other sensory modalities affect drivers’ control of their vehicles, and that drivers adapt over time to persistent changes in sensory cues (for example in driving simulators), but the mechanisms underlying these behavioural phenomena are poorly understood. Here, we consider the existing literature on how driver steering in slalom tasks is affected by down-scaling of vestibular cues, and propose, for the first time, a computational model of driver behaviour that can, based on neurobiologically plausible mechanisms, explain the empirically observed effects, namely: decreased task performance and increased steering effort during initial exposure, followed by a partial reversal of these effects as task exposure is prolonged. Unexpectedly, the model also reproduced another previously unexplained empirical finding: a local optimum for motion down-scaling, where path-tracking is better than when one-to-one motion cues are available. Overall, our findings suggest that: (1) drivers make direct use of vestibular information as part of determining appropriate steering actions, and (2) motion down-scaling causes a yaw rate underestimation phenomenon, where drivers behave as if the simulated vehicle is rotating more slowly than it is. However, (3) in the slalom task, a certain degree of such underestimation brings a path-tracking performance benefit. Furthermore, (4) behavioural adaptation in simulated slalom driving tasks may occur due to (a) down-weighting of vestibular cues, and/or (b) increased sensitivity in timing and magnitude of steering corrections, but (c) seemingly not in the form of a full compensatory rescaling of the received vestibular input. The analyses presented here provide new insights and hypotheses about simulated driving and simulator design, and the developed models can be used to support research on multisensory integration and behavioural adaptation in both driving and other task domains

    Metabolic Profiling of Children Undergoing Surgery for Congenital Heart Disease.

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    OBJECTIVE: Inflammation and metabolism are closely interlinked. Both undergo significant dysregulation following surgery for congenital heart disease, contributing to organ failure and morbidity. In this study, we combined cytokine and metabolic profiling to examine the effect of postoperative tight glycemic control compared with conventional blood glucose management on metabolic and inflammatory outcomes in children undergoing congenital heart surgery. The aim was to evaluate changes in key metabolites following congenital heart surgery and to examine the potential of metabolic profiling for stratifying patients in terms of expected clinical outcomes. DESIGN: Laboratory and clinical study. SETTING: University Hospital and Laboratory. PATIENTS: Of 28 children undergoing surgery for congenital heart disease, 15 underwent tight glycemic control postoperatively and 13 were treated conventionally. INTERVENTIONS: Metabolic profiling of blood plasma was undertaken using proton nuclear magnetic resonance spectroscopy. A panel of metabolites was measured using a curve-fitting algorithm. Inflammatory cytokines were measured by enzyme-linked immunosorbent assay. The data were assessed with respect to clinical markers of disease severity (Risk Adjusted Congenital heart surgery score-1, Pediatric Logistic Organ Dysfunction, inotrope score, duration of ventilation and pediatric ICU-free days). MEASUREMENTS AND MAIN RESULTS: Changes in metabolic and inflammatory profiles were seen over the time course from surgery to recovery, compared with the preoperative state. Tight glycemic control did not significantly alter the response profile. We identified eight metabolites (3-D-hydroxybutyrate, acetone, acetoacetate, citrate, lactate, creatine, creatinine, and alanine) associated with surgical and disease severity. The strength of proinflammatory response, particularly interleukin-8 and interleukin-6 concentrations, inversely correlated with PICU-free days at 28 days. The interleukin-6/interleukin-10 ratio directly correlated with plasma lactate. CONCLUSIONS: This is the first report on the metabolic response to cardiac surgery in children. Using nuclear magnetic resonance to monitor the patient journey, we identified metabolites whose concentrations and trajectory appeared to be associated with clinical outcome. Metabolic profiling could be useful for patient stratification and directing investigations of clinical interventions.Mr. Correia is supported by the Imperial College Stratified Medicine Graduate Training Programme in Systems Medicine and Spectroscopic Profiling (STRATiGRAD). Dr. Pathan’s institution received grant support from the British Heart Foundation (research grant) and a Higher Education Funding Council for England clinical senior lecturer award. Dr. Ng received grant support from the British Heart Foundation (Researcher salary) and received support for article research from the British Heart Foundation. Dr. Jimenez consulted for Metabometrix is employed by the Imperial College London, and received support for article research from the National Institutes of Health (NIH). Her institution received grant support from the Cardiovascular Biomedical Research Institute. Dr. Macrae is employed by Royal Brompton and Harefield NHS Foundation Trust. Dr. Holmes is employed by the Imperial College London and received support for article research. Her institution received grant support from the Imperial College London (unrelated research grants in the field of metabolic medicine). The remaining authors have disclosed that they do not have any potential conflicts of interest.This is the final published version. It first appeared at http://journals.lww.com/ccmjournal/pages/articleviewer.aspx?year=9000&issue=00000&article=97295&type=abstract

    Conflitos legais e impactos ambientais no município de Extremoz, RN, Nordeste do Brasil

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    O estudo objetivou analisar os conflitos legais em áreas protegidas e impactos ambientais no município de Extremoz-RN, localizado na zona costeira do nordeste brasileiro. Os procedimentos metodológicos envolveram a pesquisa bibliográfica, coleta de dados secundários, pesquisa de campo e elaboração cartográfica. Como impactos ambientais decorrentes das diversas formas de ocupação do solo pode-se citar o desmatamento e queima da vegetação ciliar, ocorrência de processos erosivos e assoreamento em corpos d’água e possível perda de biodiversidade pela extração de areia. Em relação aos conflitos ambientais legais, constatou-se que 11% das áreas protegidas estão ocupadas por atividades antrópicas
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