Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Example Input: Context: Several studies have shown excess mortality among hip fracture patients compared with the normal population of the same age. Finnish guidelines for medical treatment of hip fracture patients recommend anti-osteoporosis medication and the daily concomitant use of prescribed calcium and vitamin D supplements. However, whether post-fracture use of calcium and vitamin D supplements is associated with survival in such patients has not been evaluated.', "To study the association between survival in hip fracture patients and patients' sex and age, pre-fracture vitamin D status, American Society of Anesthesiologists - Physical Status (ASA-PS) class, type of fracture and post-fracture use of prescribed calcium plus vitamin D and anti-osteoporotic medication.", "The study population was 221 hip fracture patients primarily treated in acute care for a new hip fracture in 2003-4 in two Finnish hospitals. After a median of 27.5 months from the fracture, a questionnaire was sent to all patients who were still alive at the time (n = 137). The patients were queried about their use of prescribed calcium plus vitamin D supplementation and of anti-osteoporotic drugs. The follow-up time for use of anti-osteoporotic medication and prescribed calcium and vitamin D was 19.5-36 months (median 27.5 months). Data on the use of prescribed calcium plus vitamin D supplementation and anti-osteoporotic drugs were checked against information on reimbursement of drug prescriptions held by the Finnish Social Insurance Institution. A total of 4 years' (48 months') survival data for all patients in the study population was also obtained, with the dates of patient deaths being checked against Official National and Regional population statistics. Patient survival was analysed using both the Bayesian multivariate analysis and the life table method.", 'In the multivariate analysis, the combination of variables that best explained post-fracture survival was as follows: age <80 years; ASA-PS class 1-2 (ASA-PS class 1 and 2 data were combined in calculations); post-fracture use of prescribed calcium plus vitamin D supplements concomitantly with anti-osteoporotic drugs; post-fracture use of prescribed calcium plus vitamin D supplements; post-fracture use of anti-osteoporotic drugs only; and type of fracture (femoral neck or subtrochanteric). This model correctly predicted 74% of cases. At 36 months, we observed a 36% reduction in deaths in females who used prescribed calcium plus vitamin D supplementation and a corresponding 43% reduction in males. Survival of females who used anti-osteoporotic drugs concomitantly was even greater (43% reduction in deaths) over the entire follow-up period. Excess mortality was highest in females and males who used neither anti-osteoporotic drugs nor prescribed calcium and vitamin D.
Answer: Our results indicate a potential relationship between reduced mortality and post-fracture use of prescribed calcium plus vitamin D supplementation and, in females, concomitant use of anti-osteoporotic drugs. However, further investigations are needed to understand the reason for the reduction in the risk of death. Population-based, randomized, placebo-controlled trials with total mortality as the main endpoint should be conducted to verify our results.
Example Output: Is post-fracture prescribed calcium and vitamin D supplements alone or , in females , with concomitant anti-osteoporotic drugs associated with lower mortality in elderly hip fracture patients : a prospective analysis?

Example Input: Context: Low-level vagus nerve stimulation (LL-VNS) has been demonstrated to protect myocardium against acute ischemia/reperfusion (I/R) injury. However, the underlying mechanism of this protective effect remains unknown.', 'This study aimed to test the hypothesis that LL-VNS exerts cardioprotective effect on acute I/R injury in canines via antioxidative stress and antiapoptosis reactions.', 'Thirty anesthetized mongrel dogs were randomly divided into three groups: I/R group (N = 12, the left anterior descending coronary artery was occluded for 1 hour following by 1 hour reperfusion), LL-VNS group (N = 9, I/R plus LL-VNS), and sham group (N = 9, sham surgery without LL-VNS). The voltage threshold was set at 80% of the voltage required to slow the sinus rate. Infarct size was assessed with Evans Blue and triphenyltetrazolium chloride. Activity assays, TUNEL staining, and western blotting were performed to determine markers of oxidative stress and apoptosis.', 'LL-VNS significantly decreased the incidence of ventricular arrhythmias, increased vagal tone, as confirmed by heart rate viability, and reduced infarct size compared with the I/R group. This improvement was associated with a reduction in myocardial neutrophil infiltration, the inhibition of oxidative stress, and the suppression in cardiomyocyte apoptosis. In contrast, the lack of LL-VNS in the I/R group induced the opposite effect compared with the sham group.
Answer: LL-VNS exerts protective effects on myocardial I/R injury. Its potential mechanisms involve the suppression of oxidative stress and cellular apoptosis.
Example Output: Does low-Level Vagus Nerve Stimulation attenuate Myocardial Ischemic Reperfusion Injury by Antioxidative Stress and Antiapoptosis Reactions in Canines?

Example Input: Context: The bradycardic agent zatebradine (UL-FS 49) reduces heart rate without negative inotropic or proarrhythmic effects. The aim was to experimentally characterize the influence of zatebradine on arterial baroreflex sensitivity (BRS) and heart rate variability (HRV) which are generally considered as estimates of vagal activity and have prognostic value in patients after myocardial infarction (MI).', 'Conscious rats were studied 3 days after left coronary artery ligation or sham-operation (SH). BRS was determined by linear regression analysis of RR-interval and mean arterial pressure changes evoked by intravenous (i.v.) injections of methoxamine and nitroprusside. HRV at rest was calculated from high-resolution electrocardiogram-recordings.', 'In MI-rats heart rate was similar to SH-rats, mean arterial pressure was lower and both BRS and HRV were markedly reduced. Zatebradine (0.5 mg/kg i.v.) reduced heart rate in MI-rats from 400 +/- 15 to 350 +/- 19 and in SH-rats from 390 +/- 19 to 324 +/- 6 beats/min without changing mean arterial pressure. Both BRS and HRV were restored in MI- and further increased in SH-rats by the drug. Effects of 0.05, 0.5 and 5 mg/kg zatebradine revealed a dose-dependency of heart rate reduction. The lowest dose enhanced reflex bradycardia despite little effect on heart rate and lack of effect on both reflex tachycardia and HRV.
Answer: Both BRS and HRV are reduced in rats early after MI, indicating a depressed reflex and tonic vagal activity. Treatment with zatebradine enhances both BRS and HRV. These data suggest that the drug has both peripheral and central effects, leading to an increase of vagal control of heart rate.
Example Output:
Does the bradycardic agent zatebradine enhance baroreflex sensitivity and heart rate variability in rats early after myocardial infarction?