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.

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?

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.
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Q: Context: Vitamin A plays a major role in lipid metabolism. Previously, we reported that chronic vitamin A feeding (129 mg/kg) for two months normalized the abnormally high plasma HDL-cholesterol (HDL-C) levels in hypercholesterolemic obese rats by upregulating the hepatic scavenger receptor class B type 1 (SR-BI) expression. In this report, we hypothesize that the administration of a dose less than 129 mg of vitamin A/kg would also be effective in lowering the plasma HDL-C levels in these rats.', 'Changes in the activity and expression of proteins related to RCT were analyzed together with blood parameters in five-month-old male lean and obese rats supplemented with 2.6 (control group), 26, 52 and 129 mg of vitamin A/kg as retinyl palmitate for 20 weeks.', 'Vitamin A supplementation in the obese rats decreased the plasma HDL-C levels with a concomitant increase in the hepatic SR-BI expression and lipase activity compared to that observed in the control diet-fed obese rats treated with 2.6 mg of vitamin A/kg diet. Furthermore, vitamin A supplementation at doses of 52 and 129 mg/kg diet reduced the plasma lecithin cholesterol acyltransferase activity and increased the hepatic ATP-binding cassette transporter protein A1 expression in the obese rats. Interestingly, most of these changes were not observed in the lean rats fed a vitamin A-enriched diet.\Question: Does vitamin A-enriched diet modulate reverse cholesterol transport in hypercholesterolemic obese rats of the WNIN/Ob strain?

A: Chronic feeding of a vitamin A-enriched diet in hypercholesterolemic obese rats normalizes the plasma HDL-C level and presumably improves RCT, with an effective dose of 52 mg/kg diet. Further studies should focus on the pharmacological potential of vitamin A supplementation to correct an abnormal human obesity-associated lipoprotein metabolism.
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Q: Context: Although falls in people with Parkinson's disease (PD) associate with dual tasking and freezing of gait (FoG), it is not known whether falls during dual tasking are due to FoG. This study investigated the effects of a cognitive task on the occurrence of falls and FoG when subjects with PD step in response to a postural perturbation.", 'Ten subjects with PD and a history of FoG as well as 10 age-matched subjects without PD stepped in response to large, backward displacements of the support surface, with and without performing a fluency task of listing items in a category. Subjects with PD performed the task in the "off" and "on" dopaminergic medication states. We recorded the percentage of trials with FoG (a lack of step in response to the perturbation), foot-lift latencies, and trials with falls into a safety harness.', 'Dual tasking significantly increased the incidence of falls in people with PD, but subjects without PD did not fall in any condition. Dual tasking did not significantly increase trials without steps or foot-lift latencies. Falls were often coincident with a lack of step (FoG) in the single-task condition, but the increased falls with dual tasking occurred on trials with steps. Levodopa tended to decrease FoG and falls with or without dual tasking. However, medication did not significantly alter the effects of dual tasking on FoG or falls.\Question: Does dual tasking during postural stepping responses increase falls but not freezing in people with Parkinson 's disease?

A:
For people with PD and FoG, forward falls may not always be caused by FoG, particularly under attention-distracting conditions.
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