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: Although meperidine is an effective treatment of postanesthetic shivering, its mechanism of action remains unknown. Investigation of other drugs might help clarify the mechanisms by which shivering can be controlled. Accordingly, we investigated the efficacy of clonidine, an alpha 2-adrenergic agonist, and ketanserin, a 5-hydroxytryptamine antagonist, in treating postanesthetic shivering.', 'First, 54 patients shivering after general anesthesia were allocated randomly to receive an intravenous bolus of saline, 150 micrograms clonidine, or 10 mg ketanserin. A second study explored the dose-dependence of clonidine. Forty shivering patients were given saline or clonidine, 37.5, 75, or 150 micrograms.', 'The duration of shivering was significantly shorter in those given clonidine (2.1 +/- 0.9 min) than in the other two groups and shorter in the ketanserin group (4.3 +/- 0.9 min) than in the saline group (12.0 +/- 1.6 min). Clonidine and ketanserin significantly decreased systolic arterial blood pressure when compared to saline. Core rewarming was significantly slower in the clonidine group. In the second study, 37.5 micrograms clonidine was no more effective than saline. Two minutes after treatment, 150 micrograms obliterated shivering in all patients. Five minutes after treatment, all patients given 75 micrograms had stopped shivering. Systolic arterial pressure and heart rate decreased significantly in patients given 75 and 150 micrograms clonidine.\Question: Are clonidine and ketanserin both effective treatment for postanesthetic shivering?
[EX A]: Clonidine (150 micrograms) and ketanserin (10 mg) both are effective treatment for postanesthetic shivering. The effect of clonidine on shivering is dose-dependent: whereas 37.5 micrograms had no effect, 75 micrograms clonidine stopped shivering within 5 min.

[EX Q]: Context: Although current molecular clock methods offer greater flexibility in modelling evolutionary events, calibration of the clock with dates from the fossil record is still problematic for many groups. Here we implement several new approaches in molecular dating to estimate the evolutionary ages of Lacertidae, an Old World family of lizards with a poor fossil record and uncertain phylogeny. Four different models of rate variation are tested in a new program for Bayesian phylogenetic analysis called TreeTime, based on a combination of mitochondrial and nuclear gene sequences. We incorporate paleontological uncertainty into divergence estimates by expressing multiple calibration dates as a range of probabilistic distributions. We also test the reliability of our proposed calibrations by exploring effects of individual priors on posterior estimates.', 'According to the most reliable model, as indicated by Bayes factor comparison, modern lacertids arose shortly after the K/T transition and entered Africa about 45 million years ago, with the majority of their African radiation occurring in the Eocene and Oligocene. Our findings indicate much earlier origins for these clades than previously reported, and we discuss our results in light of paleogeographic trends during the Cenozoic.\Question: Does integration of Bayesian molecular clock methods and fossil-based soft bounds reveal early Cenozoic origin of African lacertid lizards?
[EX A]: This study represents the first attempt to estimate evolutionary ages of a specific group of reptiles exhibiting uncertain phylogenetic relationships, molecular rate variation and a poor fossil record. Our results emphasize the sensitivity of molecular divergence dates to fossil calibrations, and support the use of combined molecular data sets and multiple, well-spaced dates from the fossil record as minimum node constraints. The bioinformatics program used here, TreeTime, is publicly available, and we recommend its use for molecular dating of taxa faced with similar challenges.

[EX Q]: Context: The objective of this study was to examine the associations between objective measures of sleep duration and sleep efficiency with the grades obtained by healthy typically developing children in math, language, science, and art while controlling for the potential confounding effects of socioeconomic status (SES), age, and gender.', "We studied healthy typically developing children between 7 and 11 years of age. Sleep was assessed for five week nights using actigraphy, and parents provided their child's most recent report card.", 'Higher sleep efficiency (but not sleep duration) was associated with better grades in math, English language, and French as a second language, above and beyond the contributions of age, gender, and SES.\Question: Is sleep efficiency ( but not sleep duration ) of healthy school-age children associated with grades in math and languages?
[EX A]:
Sleep efficiency, but not sleep duration, is associated with academic performance as measured by report-card grades in typically developing school-aged children. The integration of strategies to improve sleep efficiency might represent a successful approach for improving children's readiness and/or performance in math and languages.