504 research outputs found

    Shoot and root morphogenesis from Eucalyptus grandis x urophylla callus

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    Eucalyptus grandis x urophylla plantlets were regenerated via indirect organogenesis. Histological assessment of their development focused on identifying the calli, the differentiation of shoots from the calli and the  shoot-root junction from the nascent shoots. Vascular tissue formation within the callus preceded that of  organised nodular structures, from which adventitious shoots were ultimately formed. Vascular systems  linked the nodular structures and their associated cambial meristems, observed at 15 to 22 days, were  hypothesized as being the centres of differentiation for shoot formation. Roots developed from isolated  adventitious shoots from either the callus created as a wounding response to isolation or from a region of the  stem immediately above the callus. Roots developed from the latter had integrated root and shoot vascular  systems, whereas those originating from the callus were not connected vascularly; however, this connection could be created during ex vitro acclimatization. The implications of the findings for increased plant yields  through indirect morphogenesis were discussed.Key words: Eucalyptus, indirect organogenesis, microscopy

    The role of oral health-related quality of life in the association between dental caries and height, weight and BMI among children in Bangladesh

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    Objectives: To examine whether oral health-related quality of life (OHRQoL) explained the negative associations between dental caries and anthropometric measures of child growth among a sample of 5- to 9-year-old children in Dhaka, Bangladesh, while taking potential confounding factors (maternal education, family income, study setting, child's birth weight and childhood diseases) into account. In addition, to test whether specific oral impacts had a role in explaining these associations. Methods: Data collection was conducted via a cross-sectional survey among children and their parents from both hospital and school settings in Dhaka. Dental caries and severe consequences of dental caries (defined here as dental sepsis) were the exposure variables, and age- and sex-adjusted height-z-scores (HAZ), weight-z-scores (WAZ) and BMI-z-scores (BAZ) were the outcome variables. OHRQoL was measured using the Bengali version of the Scale of Oral Health Outcomes for 5-year-old children (SOHO-5). First, associations between oral impacts (prevalence of overall impacts and specific items of the SOHO-5) and outcome measures were assessed. Multiple linear regression was used to assess associations between caries and anthropometric measures, adjusted for potential confounders. Oral impacts were then added to test whether their inclusion attenuated the associations between exposures and outcomes. To further investigate potential mediating role of oral impacts, structural equation modelling (SEM) was used to test the hypothesis that dental caries and sepsis were associated with the outcomes directly and also indirectly via oral impacts in general. A similar approach was used to investigate mediation by specific SOHO-5 items. Results: The sample consisted of 715 children, 73.1% of whom had dental caries, 37.5% presented with sepsis, and 57.3% reported at least one oral impact (SOHO-5 score ≄1). Prevalence of overall oral impacts and also the impact on ‘eating difficulty’ (a specific item of SOHO-5) were negatively associated with all three outcomes. Dental caries and sepsis was associated with lower HAZ, WAZ and BAZ, and adjustment for overall oral impacts considerably attenuated the associations between ‘severe dental caries’ and outcomes, and dental sepsis and outcomes. Using SEM, we found significant indirect associations between caries and sepsis and anthropometric measures via oral impacts (except for dental caries and HAZ). Considering specific oral impacts, eating difficulties explained about 44% and 65% of the associations between caries and anthropometric outcomes, and dental sepsis and anthropometric outcomes, respectively. Conclusions: Oral impacts, in particular eating difficulties, appear to mediate associations between caries and markers of child growth among this population

    Cross cultural adaptation and psychometric properties of the Bengali version of the Scale of Oral Health Outcomes for 5-year-old children (SOHO-5)

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    BACKGROUND: The oral health related quality of life (OHRQoL) of children in Bangladesh has not yet been measured, as there is no validated OHRQoL measure for that population. The aim of this study was to cross-culturally adapt the child self-report and parental proxy report versions of the Scale of Oral Health Outcomes for 5-year-old children (SOHO-5) into Bengali and test their psychometric properties: face validity, construct validity (convergent and discriminant validity) and reliability (internal consistency and test-retest reliability), among 5-9-year-old children and their parents in Bangladesh and assess associations between dental caries/sepsis and OHRQoL in this population. METHODS: The forward-backward translated Bengali SOHO-5 was piloted among 272 children and their parents to test its face validity. The questionnaire was administered to 788 children and their parents to evaluate its psychometric properties. Internal consistency of Bengali SOHO-5 was assessed using Cronbach's alpha, and test-retest reliability was assessed using Kappa. Convergent and discriminant validity were assessed through nonparametric tests. The calculation of effect sizes and standard error of measurement facilitated the assessment of minimally important difference (MID) for SOHO-5. The associations of reporting an oral impact with caries and sepsis were assessed via logistic regression models. RESULTS: Both child self-report and parental proxy report questionnaires showed good face validity. Cronbach's alpha scores were 0.79 and 0.87 for child and parental questionnaire, respectively. A weighted Kappa score of 0.85 demonstrated test-retest reliability of child questionnaire. SOHO-5 scores were significantly associated with subjective oral health outcomes and discriminated clearly between different caries severity and sepsis groups. These differences were considerably higher than the MID. After adjusting for child's age, sex, setting, maternal education and family income, the odds of reporting an oral impact were 2.25 (95% CI 1.98-2.56) and 4.44 (95% CI 3.14-6.28) times higher for each additional tooth with caries and sepsis, respectively. CONCLUSION: This study provided strong evidence supporting the validity and reliability of both versions of Bengali SOHO-5 as OHRQoL measures. Dental caries and sepsis were associated with poor OHRQoL in this population. The Bengali SOHO-5 is expected to be a useful outcome measure for research and clinical purposes in Bengali speaking child populations

    Absence of renal hypoxia in the subacute phase of severe renal ischemia reperfusion injury

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     This is the author accepted manuscript. The final version is available from American Physiological Society via the DOI in this recordTissue hypoxia has been proposed as an important event in renal ischemia reperfusion injury (IRI) particularly during the period of ischemia and in the immediate hours following reperfusion. However, little is known about renal oxygenation during the subacute phase of IRI. We employed four different methods to assess the temporal and spatial changes in tissue oxygenation during the subacute phase (24 h and 5 days after reperfusion) of a severe form of renal IRI in rats. We hypothesized that the kidney is hypoxic 24 h and 5 days after an hour of bilateral renal ischemia, driven by a disturbed balance between renal oxygen delivery (DO2) and oxygen consumption (VO2). Renal DO2 was not significantly reduced in the subacute phase of IRI. In contrast, renal VO2 was 55% less 24 h, and 49% less 5 days after reperfusion than after sham-ischemia. Inner medullary tissue PO2, measured by radiotelemetry was 25 {plus minus} 12% greater 24 h after ischemia than after sham-ischemia. By 5 days after reperfusion, tissue PO2 was similar to that in rats subjected to sham-ischemia. Tissue PO2 measured by Clark electrode was consistently greater 24 h, but not 5 days, after ischemia than after sham-ischemia. Cellular hypoxia, assessed by pimonidazole adduct immunohistochemistry, was largely absent at both time-points and tissue levels of hypoxia inducible factors were downregulated following renal ischemia. Thus, in this model of severe IRI, tissue hypoxia does not appear to be an obligatory event during the subacute phase, likely due to the markedly reduced oxygen consumption.British Heart FoundationBritish Heart FoundationNational Health and Medical Research Council of AustraliaEuropean Union, Seventh Framework Programm

    The Imprint of Galaxy Formation on X-ray Clusters

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    It is widely believed that structure in the Universe evolves hierarchically, as primordial density fluctuations, amplified by gravity, collapse and merge to form progressively larger systems. The structure and evolution of X-ray clusters, however, seems at odds with this hierarchical scenario for structure formation. Poor clusters and groups, as well as most distant clusters detected to date, are substantially fainter than expected from the tight relations between luminosity, temperature and redshift predicted by these models. Here we show that these discrepancies arise because, near the centre, the entropy of the hot, diffuse intracluster medium (ICM) is higher thaachievablethroughgravitationalcollapse,indicatingsubstantialnon−gravitationalheatingoftheICM.Weestimatethisexcessentropyforthefirsttime,andarguethatitrepresentsarelicoftheenergeticwindsthroughwhichforminggalaxiespollutedtheICMwithmetals.Energetically,thisisonl achievable through gravitational collapse, indicating substantial non-gravitational heating of the ICM. We estimate this excess entropy for the first time, and argue that it represents a relic of the energetic winds through which forming galaxies polluted the ICM with metals. Energetically, this is onl possible if the ICM is heated at modest redshift (z \ltsim 2) but prior to cluster collapse, indicating that the formation of galaxies precedes that of clusters and that most clusters have been assembled very recently.Comment: 5 pages, plus 2 postscript figures (one in colour), accepted for publication in Natur

    Comparison and relative utility of inequality measurements: as applied to Scotland’s child dental health

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    This study compared and assessed the utility of tests of inequality on a series of very large population caries datasets. National cross-sectional caries datasets for Scotland’s 5-year-olds in 1993/94 (n = 5,078); 1995/96 (n = 6,240); 1997/98 (n = 6,584); 1999/00 (n = 6,781); 2002/03 (n = 9,747); 2003/04 (n = 10,956); 2005/06 (n = 10,945) and 2007/08 (n = 12,067) were obtained. Outcomes were based on the d3mft metric (i.e. the number of decayed, missing and filled teeth). An area-based deprivation category (DepCat) measured the subjects’ socioeconomic status (SES). Simple absolute and relative inequality, Odds Ratios and the Significant Caries Index (SIC) as advocated by the World Health Organization were calculated. The measures of complex inequality applied to data were: the Slope Index of Inequality (absolute) and a variety of relative inequality tests i.e. Gini coefficient; Relative Index of Inequality; concentration curve; Koolman and Doorslaer’s transformed Concentration Index; Receiver Operator Curve and Population Attributable Risk (PAR). Additional tests used were plots of SIC deciles (SIC10) and a Scottish Caries Inequality Metric (SCIM10). Over the period, mean d3mft improved from 3.1(95%CI 3.0–3.2) to 1.9(95%CI 1.8–1.9) and d3mft = 0% from 41.1(95%CI 39.8–42.3) to 58.3(95%CI 57.8–59.7). Absolute simple and complex inequality decreased. Relative simple and complex inequality remained comparatively stable. Our results support the use of the SII and RII to measure complex absolute and relative SES inequalities alongside additional tests of complex relative inequality such as PAR and Koolman and Doorslaer’s transformed CI. The latter two have clear interpretations which may influence policy makers. Specialised dental metrics (i.e. SIC, SIC10 and SCIM10) permit the exploration of other important inequalities not determined by SES, and could be applied to many other types of disease where ranking of morbidity is possible e.g. obesity. More generally, the approaches described may be applied to study patterns of health inequality affecting worldwide populations

    Argumentation in school science : Breaking the tradition of authoritative exposition through a pedagogy that promotes discussion and reasoning

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    The value of argumentation in science education has become internationally recognised and has been the subject of many research studies in recent years. Successful introduction of argumentation activities in learning contexts involves extending teaching goals beyond the understanding of facts and concepts, to include an emphasis on cognitive and metacognitive processes, epistemic criteria and reasoning. The authors focus on the difficulties inherent in shifting a tradition of teaching from one dominated by authoritative exposition to one that is more dialogic, involving small-group discussion based on tasks that stimulate argumentation. The paper builds on previous research on enhancing the quality of argument in school science, to focus on how argumentation activities have been designed, with appropriate strategies, resources and modelling, for pedagogical purposes. The paper analyses design frameworks, their contexts and lesson plans, to evaluate their potential for enhancing reasoning through foregrounding the processes of argumentation. Examples of classroom dialogue where teachers adopt the frameworks/plans are analysed to show how argumentation processes are scaffolded. The analysis shows that several layers of interpretation are needed and these layers need to be aligned for successful implementation. The analysis serves to highlight the potential and limitations of the design frameworks

    Further investigation of confirmed urinary tract infection (UTI) in children under five years: a systematic review.

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    Background: Further investigation of confirmed UTI in children aims to prevent renal scarring and future complications. Methods: We conducted a systematic review to determine the most effective approach to the further investigation of confirmed urinary tract infection (UTI) in children under five years of age. Results: 73 studies were included. Many studies had methodological limitations or were poorly reported. Effectiveness of further investigations: One study found that routine imaging did not lead to a reduction in recurrent UTIs or renal scarring. Diagnostic accuracy: The studies do not support the use of less invasive tests such as ultrasound as an alternative to renal scintigraphy, either to rule out infection of the upper urinary tract (LR- = 0.57, 95%CI: 0.47, 0.68) and thus to exclude patients from further investigation or to detect renal scarring (LR+ = 3.5, 95% CI: 2.5, 4.8). None of the tests investigated can accurately predict the development of renal scarring. The available evidence supports the consideration of contrast-enhanced ultrasound techniques for detecting vesico-ureteric reflux (VUR), as an alternative to micturating cystourethrography (MCUG) (LR+ = 14.1, 95% CI: 9.5, 20.8; LR- = 0.20, 95%CI: 0.13, 0.29); these techniques have the advantage of not requiring exposure to ionising radiation. Conclusion: There is no evidence to support the clinical effectiveness of routine investigation of children with confirmed UTI. Primary research on the effectiveness, in terms of improved patient outcome, of testing at all stages in the investigation of confirmed urinary tract infection is urgently required

    Predicting understory maximum shrubs cover using altitude and overstory basal area in different Mediterranean forests

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    In some areas of the Mediterranean basin where the understory stratum represents a critical fire hazard, managing the canopy cover to control the understory shrubby vegetation is an ecological alternative to the current mechanical management techniques. In this study, we determine the relationship between the overstory basal area and the cover of the understory shrubby vegetation for different dominant canopy species (Pinaceae and Fagaceae species) along a wide altitudinal gradient in the province of Catalonia (Spain). Analyses were conducted using data from the Spanish National Forest Inventory. At the regional scale, when all stands are analysed together, a strong negative relationship between mean shrub cover and site elevation was found. Among the Pinaceae species, we found fairly good relationships between stand basal area and the maximum development of the shrub stratum for species located at intermediate elevations (Pinus nigra, Pinus sylvestris). However, at the extremes of the elevationclimatic gradient (Pinus halepensis and Pinus uncinata stands), stand basal area explained very little of the shrub cover variation probably because microsite and topographic factors override its effect. Among the Fagaceae species, a negative relationship between basal area and the maximum development of the shrub stratum was found in Quercus humilis and Fagus sylvatica dominated stands but not in Quercus ilex. This can be due to the particular canopy structure and management history of Q. ilex stands. In conclusion, our study revealed a marked effect of the tree layer composition and the environment on the relationship between the development of the understory and overstory tree structure. More fine-grained studies are needed to provide forest managers with more detailed information about the relationship between these two forest strata
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