In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

[EX Q]: Context: RNA editing is the process whereby an RNA sequence is modified from the sequence of the corresponding DNA template. In the mitochondria of land plants, some cytidines are converted to uridines before translation. Despite substantial study, the molecular biological mechanism by which C-to-U RNA editing proceeds remains relatively obscure, although several experimental studies have implicated a role for cis-recognition. A highly non-random distribution of nucleotides is observed in the immediate vicinity of edited sites (within 20 nucleotides 5' and 3'), but no precise consensus motif has been identified.", "Data for analysis were derived from the the complete mitochondrial genomes of Arabidopsis thaliana, Brassica napus, and Oryza sativa; additionally, a combined data set of observations across all three genomes was generated. We selected datasets based on the 20 nucleotides 5' and the 20 nucleotides 3' of edited sites and an equivalently sized and appropriately constructed null-set of non-edited sites. We used tree-based statistical methods and random forests to generate models of C-to-U RNA editing based on the nucleotides surrounding the edited/non-edited sites and on the estimated folding energies of those regions. Tree-based statistical methods based on primary sequence data surrounding edited/non-edited sites and estimates of free energy of folding yield models with optimistic re-substitution-based estimates of approximately 0.71 accuracy, approximately 0.64 sensitivity, and approximately 0.88 specificity. Random forest analysis yielded better models and more exact performance estimates with approximately 0.74 accuracy, approximately 0.72 sensitivity, and approximately 0.81 specificity for the combined observations.\Question: Do simple statistical models predict C-to-U edited sites in plant mitochondrial RNA?
[EX A]: Simple models do moderately well in predicting which cytidines will be edited to uridines, and provide the first quantitative predictive models for RNA edited sites in plant mitochondria. Our analysis shows that the identity of the nucleotide -1 to the edited C and the estimated free energy of folding for a 41 nt region surrounding the edited C are the most important variables that distinguish most edited from non-edited sites. However, the results suggest that primary sequence data and simple free energy of folding calculations alone are insufficient to make highly accurate predictions.

[EX Q]: Context: Hypercontracture is an important mechanism of myocyte death during reperfusion. cGMP modulates the sensitivity of contractile myofilaments to Ca2+, and increasing cGMP concentration during the last minutes of anoxia prevents reoxygenation-induced hypercontracture in isolated cardiomyocytes. The purpose of this study was to determine whether stimulation of particulate guanylyl cyclase with the natriuretic peptide urodilatin, given at the time of reperfusion, reduces myocardial necrosis in the rat heart submitted to transient ischemia.', 'Isolated rat hearts (n = 38) were submitted to either 40 or 60 min of no-flow ischemia and 2 h of reperfusion, and were allocated to receive or not receive 0.05 microM urodilatin during the first 15 min of reperfusion or non-reperfusion treatment.', 'A marked reduction in myocardial cGMP concentration was observed in control hearts during reperfusion after 40 or 60 min of ischemia. Urodilatin significantly attenuated cGMP depletion during initial reperfusion, markedly improved contractile recovery after 40 min of ischemia (P < 0.0309), and reduced reperfusion-induced increase in left ventricular end-diastolic pressure (P = 0.0139), LDH release (P = 0.0263), and contraction band necrosis (P = 0.0179) after 60 min of ischemia. The beneficial effect of urodilatin was reproduced by the membrane permeable cGMP analog 8-Bromo-cGMP.\Question: Does urodilatin limit acute reperfusion injury in the isolated rat heart?
[EX A]: These results indicate that reduced cGMP concentration may impair myocyte survival during reperfusion. Stimulation of particulate guanylyl cyclase may appear as a new strategy to prevent immediate lethal reperfusion injury.

[EX Q]: Context: CENTRAL, Medline, Embase, Web of Science, LILACS and BBO databases, the Brazilian database of thesis and dissertations (Banco de Teses CAPES), a Brazilian register of ethically approved projects involving human beings (SISNEP) and two registers of ongoing trials (Current Controlled Trials and Clinical-Trials.gov). Reference lists were also scanned for relevant papers. Study authors were contacted for additional information.', 'Individual or cluster-randomised or quasi-randomised controlled trials conducted in children under seven were included.', 'Study selection and data abstraction were conducted by two reviewers independently. Risk of bias assessment was undertaken using the Cochrane Collaboration tool. Meta-analyses of prevented fractions (PF) were performed to assess the effect of fluoride toothpaste on the dmft and dmfs. Meta-analyses were also performed to obtain a pooled relative risk (RR) to assess the effect of fluoride toothpastes on the proportion of children developing caries.', 'Eight studies were included. When standard F toothpastes were compared to placebo or no intervention, significant caries reduction at surface (PF = 31%; 95% CI 18-43; 2644 participants in five studies), tooth (PF = 16%; 95% CI 8-25; 2555 participants in one study) and individual (RR = 0.86; 95% CI 0.81-0.93; 2806 participants in two studies) level were observed. Low F toothpastes were effective only at surface level (PF = 40%; 95% CI 5-75; 561 participants in two studies).\Question: Does limited evidence suggest standard fluoride toothpaste reduces caries potential in preschool children?
[EX A]:
Standard F toothpastes are effective in reducing dental caries in the primary teeth of preschool children and thus their use should be recommended to this age group.