338 research outputs found

    A method for the determination of solanesol in tobacco

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    The object or this work was to develop a procedure for the quantitative determination of solanesol in the petroleum ether extract of tobacco. The amount of tobacco extracted into petroleum ether is routinely used to differentiate tobacco types. The extraction procedures have been extensively studied by the Association of Official Agricultural Chemists (AOAC) and reported in the United States Department of Agriculture (USDA) Technical Bulletin # 1186. There is at present no method for the quantitative determination of solanesol. One procedure which comes closest, involves an infrared measurement of the tobacco extract. Because of the presence of other bands, the results are reported as solanesol-like substances rather than solanesol. The reported values are considerably higher than estimates obtained from large scale isolation of solanesol from tobacco

    Olfactory cues of mahogany trees to female Hypsipyla robusta

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    Abstract The mahogany shoot borer, Hypsipyla robusta (Moore) (Lepidoptera Pyralidae), is a serious pest insect in the tropical forests of Africa, Asia and Australia. This insect causes multiple branching of young shoots in indigenous mahogany plantations. Gravid insects are attracted to oviposition sites by volatile organic compounds (VOCs) released by their hosts. Therefore, in this study, we aimed to (i) identify and characterise the VOCs released by the shoots of Entandrophragma and Khaya mahogany and (ii) to determine the electrophysiologically active VOCs which could influence the olfactory response of H. robusta. Volatile samples were collected from shoots of Entandrophragma angolense (Welwitsch) de Candolle, Entandrophragma utile (Dawe et Sprague) Sprague, Khaya anthotheca (Welwitsch) de Candolle and Khaya ivorensis Chevalier by closed-loop-stripping-analysis. The VOCs were identified by gas-chromatography mass-spectrometry (GC-MS) and characterised by comparing their retention times with those of authentic standards. For the first time, 29 VOCs were characterised as typical of the four mahogany species studied. The VOCs included alcohols, aldehydes, alkanes, alkenes, esters, ketones, monoterpenes, alcohol sesquiterpenes and sesquiterpenes. The majority were esters (10) and sesquiterpenes (8). GC-MS/electroantennographic detection experiments revealed antennal responses of the female moth to (Z)-ÎČ-ocimene, (Z)-3-hexen-1-yl acetate, hexan-1-ol, nonanal, (Z)-3-hexen-1-yl butanoate, 2-ethyl hexan-1-ol, decanal, ÎČ-caryophyllene, (Z)-3-hexen-1-yl hexanoate and germacrene D. Dose-response experiments with three of the compounds revealed antennal responses at concentrations of 10 -7 to 10 -2 . We therefore suggest that these compounds are olfactory cues of female H. robusta and could be used in behaviour-based control of H. robusta

    Children as Bellwethers of Recovery: Dysfunctional Systems and the Effects of Parents, Households, and Neighborhoods on Serious Emotional Disturbance in Children After Hurricane Katrina

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    Background: Over 160 000 children were displaced from their homes after Hurricane Katrina. Tens of thousands of these children experienced the ongoing chaos and uncertainty of displacement and transiency, as well as significant social disruptions in their lives. The objectives of this study were to estimate the long-term mental health effects of such exposure among children, and to elucidate the systemic pathways through which the disaster effect operates. Methods: The prevalence of serious emotional disturbance was assessed among 283 school-aged children in Louisiana and Mississippi. These children are part of the Gulf Coast Child & Family Health Study, involving a longitudinal cohort of 1079 randomly sampled households in the two states, encompassing a total of 427 children, who have been interviewed in 4 annual waves of data collection since January 2006. The majority of data for this analysis was drawn from the fourth round of data. Results: Although access to medical care for children has expanded considerably since 2005 in the region affected by Hurricane Katrina, more than 37% of children have received a clinical mental health diagnosis of depression, anxiety, or behavior disorder, according to parent reports. Children exposed to Hurricane Katrina were nearly 5 times as likely as a pre-Katrina cohort to exhibit serious emotional disturbance. Path analyses confirm the roles played by neighborhood social disorder, household stressors, and parental limitations on children's emotional and behavioral functioning. Conclusions: Children and youth are particularly vulnerable to the effects of disasters. They have limited capacity to independently mobilize resources to help them adapt to stressful postdisaster circumstances, and are instead dependent upon others to make choices that will influence their household, neighborhood, school, and larger social environment. Children's mental health recovery in a postdisaster setting can serve as a bellwether indicator of successful recovery or as a lagging indicator of system dysfunction and failed recovery

    Clinical Findings in Four Children with Biotinidase Deficiency Detected through a Statewide Neonatal Screening Program

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    Four children with biotinidase deficiency were identified during the first year of a neonatal screening program for this disease in the Commonwealth of Virginia. Two unrelated probands were identified among the 81,243 newborn infants who were screened. In addition, two siblings of one of these infants were found to be affected. Both probands had mild neurologic symptoms at two and four months, respectively, and the two older children had more severe neurologic abnormalities, cutaneous findings, and developmental delay at two and three years of age. However, none of the affected children had acute metabolic decompensation. Previous studies have shown that the administration of biotin to affected children can be a lifesaving procedure that can reverse acute symptoms and prevent irreversible neurologic damage. Our findings demonstrate that subtle neurologic abnormalities may appear as early as at two months of age and that developmental abnormalities may occur even in the absence of episodes of overt metabolic decompensation. Since screening and treatment are both inexpensive and effective and the incidence of the disease is well within the range of that of other metabolic diseases for which screening is performed, biotinidase deficiency should be added to the group of metabolic diseases for which screening is done in the neonatal period. (N Engl J Med 1985; 313:16–9.

    Action Research with Children: Lessons from Tackling Disasters and Climate Change

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    Recent research and practice from the fields of climate change adaptation and disaster management has created a shift from emphasis of children's vulnerability and need for protection towards their potential as agents of change before, during and after disaster events. This article examines lessons from action research into children's agency in disaster?prone communities of El Salvador and the Philippines. We describe some of the participatory risk management methods that were adapted for use with children, the centrality of ethics to our approach and the importance of working with a non?governmental organisation (NGO) partner that provides ongoing support in the study communities. The research design was led by external agents in order to cross?compare findings across locations and countries. However, we argue that by engaging children in a process of knowledge generation and analysis, the research broke down some of the assumed hierarchies between researcher and researched common to orthodox approaches

    Importance sampling method of correction for multiple testing in affected sib-pair linkage analysis

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    Using the Genetic Analysis Workshop 13 simulated data set, we compared the technique of importance sampling to several other methods designed to adjust p-values for multiple testing: the Bonferroni correction, the method proposed by Feingold et al., and naĂŻve Monte Carlo simulation. We performed affected sib-pair linkage analysis for each of the 100 replicates for each of five binary traits and adjusted the derived p-values using each of the correction methods. The type I error rates for each correction method and the ability of each of the methods to detect loci known to influence trait values were compared. All of the methods considered were conservative with respect to type I error, especially the Bonferroni method. The ability of these methods to detect trait loci was also low. However, this may be partially due to a limitation inherent in our binary trait definitions

    Shifting the Narrative: Child-led Responses to Climate Change and Disasters in El Salvador and the Philippines

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    Children and young people are commonly treated in the climate change and disasters literature as victims of natural events requiring protection by adults. This article critiques that narrative, drawing on examples from the Philippines and El Salvador that explore how children’s groups have responded to such issues through child‐centred initiatives. This highlights the importance of understanding children’s perception and communication of risks facing their lives and livelihoods, their potential as agents of change in preventing disasters and adapting to climate change, and the implications for the theory and practice of child participation, particularly in developing countries
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