217 research outputs found

    Proposed magnetostratigraphy susceptibility magnetostratotype for the Eifelian-Givetian GSSP (Anti-Atlas, Morocco)

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    The magnetosusceptibility event and cyclostratigraphy (MSEC) record for the Eifelian-Givetian Global Boundary Stratotype Section and Point (GSSP) located in the western Sahara of southeastern Morocco is used to establish a sequence of magnetostratigraphic susceptibility units organized into magnetostratigraphic susceptibility zones (MSZ) and magnetostratigraphic susceptibility subzones (MSSZ). Magnetic susceptibility data are summarized into two complete MSZs (Atrous and Mech Irdane) and two partial MSZs (Gheris and Rissani). The Atrous (Upper Eifelian) is comprised of 3 MSSZs and the Mech Irdane (uppermost Eifelian and lowermost Givetian) of 11 MSSZs. The Eifelian-Givetian boundary falls within Mech Irdane MSSZ 2 making the magnetosubzone an important boundary marker unit. Large-scale transgressive and regressive patterns in the MSEC data establish that the Eifelian-Givetian boundary in the GSSP sequence occurs immediately after the first regressive pulse following the transgressive conditions established during the Atrous MSZ. The Lower Kačák/otomari Event occurs in Atrous MSSZ 3 and Kačák/otomari Event occurs in Mech Irdane MSSZ 1. The magnetic properties of the MSZs and MSSZs are tested by comparison with a coeval magnetostratigraphic susceptibility sequence in the Montagne Noire region of southern France

    The Global Asthma Network rationale and methods for Phase I global surveillance: prevalence, severity, management and risk factors.

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    The Global Asthma Network (GAN), established in 2012, followed the International Study of Asthma and Allergies in Childhood (ISAAC). ISAAC Phase One involved over 700 000 adolescents and children from 156 centres in 56 countries; it found marked worldwide variation in symptom prevalence of asthma, rhinitis and eczema that was not explained by the current understanding of these diseases; ISAAC Phase Three involved over 1 187 496 adolescents and children (237 centres in 98 countries). It found that asthma symptom prevalence was increasing in many locations especially in low- and middle-income countries where severity was also high, and identified several environmental factors that required further investigation.GAN Phase I, described in this article, builds on the ISAAC findings by collecting further information on asthma, rhinitis and eczema prevalence, severity, diagnoses, asthma emergency room visits, hospital admissions, management and use of asthma essential medicines. The subjects will be the same age groups as ISAAC, and their parents. In this first global monitoring of asthma in children and adults since 2003, further evidence will be obtained to understand asthma, management practices and risk factors, leading to further recognition that asthma is an important non-communicable disease and to reduce its global burden

    Global Asthma Network survey suggests more national asthma strategies could reduce burden of asthma.

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    BACKGROUND: Several countries or regions within countries have an effective national asthma strategy resulting in a reduction of the large burden of asthma to individuals and society. There has been no systematic appraisal of the extent of national asthma strategies in the world. METHODS: The Global Asthma Network (GAN) undertook an email survey of 276 Principal Investigators of GAN centres in 120 countries, in 2013-2014. One of the questions was: "Has a national asthma strategy been developed in your country for the next five years? For children? For adults?". RESULTS: Investigators in 112 (93.3%) countries answered this question. Of these, 26 (23.2%) reported having a national asthma strategy for children and 24 (21.4%) for adults; 22 (19.6%) countries had a strategy for both children and adults; 28 (25%) had a strategy for at least one age group. In countries with a high prevalence of current wheeze, strategies were significantly more common than in low prevalence countries (11/13 (85%) and 7/31 (22.6%) respectively, p<0.001). INTERPRETATION: In 25% countries a national asthma strategy was reported. A large reduction in the global burden of asthma could be potentially achieved if more countries had an effective asthma strategy

    Calling time on asthma deaths in tropical regions—how much longer must people wait for essential medicines?

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    Every day around 1150 people die worldwide because of asthma, and most of these deaths are avoidable.1 As a comparison, malaria—which is seen as a much bigger problem and increased prevention measures have resulted in decreasing death rates—kills about 1175 people per day.2 Most asthma deaths occur in children and adults living in tropical regions, where effective asthma management might be either non-existent or inaccessible.3 However, with correct diagnosis and treatment many deaths from asthma could be prevented

    The burden of asthma, hay fever and eczema in children in 25 countries: GAN Phase I study

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    AIMS: There have been no worldwide standardised surveys of prevalence and severity of asthma, rhinoconjunctivitis and eczema in school children for 15 years. The present study aims to provide this information. METHODS: Following the exact International Study of Asthma and Allergies in Childhood (ISAAC) methodology (cross-sectional questionnaire-based survey), Global Asthma Network (GAN) Phase I was carried out between 2015 and 2020 in many centres worldwide. RESULTS: The study included 157 784 adolescents (13-14 years of age) in 63 centres in 25 countries and 101 777 children (6-7 years of age) in 44 centres in 16 countries. The current prevalence of symptoms, respectively, was 11.0% and 9.1% for asthma, 13.3% and 7.7% for rhinoconjunctivitis and 6.4% and 5.9% for eczema. The prevalence of asthma ever was 10.5% and 7.6%, hay fever ever was 15.2% and 11.1% and eczema ever was 10.6% and 13.4%, respectively. Centres in low or lower middle gross national income countries (LICs or LMICs) had significantly lower prevalence of the three disease symptoms and diagnoses (except for hay fever). In children, the prevalence of asthma and rhinoconjunctivitis symptoms was higher in boys, while the reverse occurred among adolescents. For eczema, while the prevalence among female adolescents was double that of males, there was no sex difference among children. Centre accounted for non-negligible variability in all disease symptoms (10-20%). CONCLUSION: The burdens of asthma, rhinoconjunctivitis and eczema vary widely among the limited number of countries studied. Although symptom prevalence is lower in LICs and LMICs, it represents a considerable burden everywhere studied

    Strengthening the impact of plant genetic resources through collaborative collection, conservation, characterisation, and evaluation: a tribute to the legacy of Dr Clive Francis

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    This paper is a tribute to the legacy of Dr Clive Francis, who directly and indirectly collected >14 000 accessions across 60 genera of pasture, forage, and crop species and their wild relatives around the Mediterranean basin, Eastern Africa, and Central and South Asia from 1973 to 2005. This was achieved by a collaborative approach that built strong interactions between disparate organisations (ICARDA, VIR, CLIMA, and Australian genebanks) based on germplasm exchange, conservation and documentation, capacity building, and joint collection. These activities greatly strengthened Australian pasture, forage, and crop genebanks, and led to widespread germplasm utilisation that has waned in the last 5 years, reflecting changing priorities among industry funding bodies and research providers. This situation must be reversed, given the pivotal role genetic resource collections must play to broaden the genetic and adaptive base of plant breeding, to meet the challenge of feeding an increasing population in a depleting resource base. Because the use of germplasm subsets that facilitate phenotyping will stimulate wider utilisation of genetic resources, we discuss the application of core collection and germplasm selection through habitat characterisation/filtering in Australian collections. Both are valid entry points into large collections, but the latter has the advantage of enabling both trait discovery and investigation of plant adaptation, and because it is based on a priori hypothesis testing, it increases understanding even when the trait of interest is not identified

    Reproducibility of left ventricular mass by echocardiogram in the ELSA-Brasil

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    Fundamento: A ecocardiografia, apesar de não invasiva e de relativo baixo custo, tem na variabilidade de medidas repetidas um dos principais limitantes a sua utilização em estudos epidemiológicos. Objetivo: Avaliar a reprodutibilidade da massa ventricular esquerda obtida em centros de investigação (on-line) com aquela obtida em centro de leitura (off-line) e entre medidas realizadas por diferentes avaliadores no centro de leitura. Método: Ecocardiografistas dos seis centros de investigação do ELSA-Brasil mediram on-line a massa ventricular esquerda e outras medidas ecocardiográficas de 124 exames antes de enviá-los ao centro de leitura, onde foram lidos off-line de acordo com o protocolo do estudo. Metade desses exames foi medida de forma cega por um segundo leitor. Resultados: Dos 124 exames, cinco (4%) foram considerados não mensuráveis. Dos 119 restantes, 72 (61%) eram de mulheres, com idade média de 50,2 ± 7,0 anos, sendo apenas dois exames com alteração estrutural cardíaca. Em 110 (92,4%) dos exames, as imagens foram consideradas ótimas/boas pelo centro de leitura. Não foram observadas diferenças significativas entre as médias da massa ventricular esquerda obtidas on-line e off-line (1,29 g, IC 95% −3,60-6,19), sendo o coeficiente de correlação intraclasse de 0,79 (IC 95% 0,72-0,85). Para as medidas realizadas no centro de leitura, % 0,78-0,91). Conclusão: Não houve diferenças sistemáticas relevantes na medida da massa ventricular esquerda on-line versus off-line e a reprodutibilidade das medidas foi similar à de estudos anteriores. A realização das medidas em centros de leitura, como utilizado no ELSA-Brasil, é factível e útil em estudos clínico-epidemiológicos realizados em nosso meio.Background: Echocardiography, though non-invasive and having relatively low-cost, presents issues of variability which can limit its use in epidemiological studies. Objectives: To evaluate left ventricular mass reproducibility when assessed at acquisition (online) compared to when assessed at a reading center after electronic transmission (offline) and also when assessed by different readers at the reading center. Method: Echocardiographers from the 6 ELSA-Brasil study investigation centers measured the left ventricular mass online during the acquisition from 124 studies before transmitting to the reading center, where studies were read according to the study protocol. Half of these studies were blindly read by a second reader in the reading center. Results: From the 124 echocardiograms, 5 (4%) were considered not measurable. Among the remaining 119, 72 (61%) were women, mean age was 50.2 ± 7.0 years and 2 had structural myocardial abnormalities. Images were considered to be optimal/good by the reading center for 110 (92.4%) cases. No significant difference existed between online and offline measurements (1,29g, CI 95% −3.60-6.19), and the intraclass correlation coefficientbetween them was 0.79 (CI 95% 0.71-0.85). For images read by two readers, the intraclass correlation coefficient was 0.86 (CI 95% 0.78-0.91). Conclusion: There were no significant drifts between online and offline left ventricular mass measurements, and reproducibility was similar to that described in previous studies. Central quantitative assessment of echocardiographic studies in reading centers, as performed in the ELSA-Brasil study, is feasible and useful in clinical and epidemiological studies performed in our setting

    Non-lethal control of the cariogenic potential of an agent-based model for dental plaque

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    Dental caries or tooth decay is a prevalent global disease whose causative agent is the oral biofilm known as plaque. According to the ecological plaque hypothesis, this biofilm becomes pathogenic when external challenges drive it towards a state with a high proportion of acid-producing bacteria. Determining which factors control biofilm composition is therefore desirable when developing novel clinical treatments to combat caries, but is also challenging due to the system complexity and the existence of multiple bacterial species performing similar functions. Here we employ agent-based mathematical modelling to simulate a biofilm consisting of two competing, distinct types of bacterial populations, each parameterised by their nutrient uptake and aciduricity, periodically subjected to an acid challenge resulting from the metabolism of dietary carbohydrates. It was found that one population was progressively eliminated from the system to give either a benign or a pathogenic biofilm, with a tipping point between these two fates depending on a multiplicity of factors relating to microbial physiology and biofilm geometry. Parameter sensitivity was quantified by individually varying the model parameters against putative experimental measures, suggesting non-lethal interventions that can favourably modulate biofilm composition. We discuss how the same parameter sensitivity data can be used to guide the design of validation experiments, and argue for the benefits of in silico modelling in providing an additional predictive capability upstream from in vitro experiments
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