Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
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Question: Context: Previous X-ray crystal structures have shown that linkers of five amino acid residues connecting pairs of chicken brain alpha-spectrin and human erythroid beta-spectrin repeats can undergo bending without losing their alpha-helical structure. To test whether bending at one linker can influence bending at an adjacent linker, the structures of two and three repeat fragments of chicken brain alpha-spectrin have been determined by X-ray crystallography. The structure of the three-repeat fragment clearly shows that bending at one linker can occur independently of bending at an adjacent linker. This observation increases the possible trajectories of modeled chains of spectrin repeats. Furthermore, the three-repeat molecule crystallized as an antiparallel dimer with a significantly smaller buried interfacial area than that of alpha-actinin, a spectrin-related molecule, but large enough and of a type indicating biological specificity. Comparison of the structures of the spectrin and alpha-actinin dimers supports weak association of the former, which could not be detected by analytical ultracentrifugation, versus strong association of the latter, which has been observed by others. To correlate features of the structure with solution properties and to test a previous model of stable spectrin and dystrophin repeats, the number of inter-helical interactions in each repeat of several spectrin structures were counted and compared to their thermal stabilities. Inter-helical interactions, but not all interactions, increased in parallel with measured thermal stabilities of each repeat and in agreement with the thermal stabilities of two and three repeats and also partial repeats of spectrin. 
 Question: Alpha-spectrin and beta-spectrin subunits form parallel or antiparallel heterodimers?

Answer: antiparallel


Question: Context: In the present study, we tested the hypothesis that having migraine in middle age is related to late-life parkinsonism and a related disorder, restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED). The AGES-Reykjavik cohort (born 1907-1935) has been followed since 1967. Headaches were classified based on symptoms assessed in middle age. From 2002 to 2006, 5,764 participants were reexamined to assess symptoms of parkinsonism, diagnosis of Parkinson disease (PD), family history of PD, and RLS/WED. Subjects with midlife migraine, particularly migraine with aura (MA), were in later life more likely than others to report parkinsonian symptoms (odds ratio [OR]MA = 3.6 [95% CI 2.7-4.8]) and diagnosed PD (ORMA = 2.5 [95% CI 1.2-5.2]). Women with MA were more likely than others to have a parent (ORMA = 2.26 [95% CI 1.3-4.0]) or sibling (ORMA = 1.78 [95% CI 1.1-2.9]) with PD. Late-life RLS/WED was increased for headache generally. Associations were independent of cardiovascular disease and MRI-evident presumed ischemic lesions. These findings suggest there may be a common vulnerability to, or consequences of, migraine and multiple indicators of parkinsonism. Additional genetic and longitudinal observational studies are needed to identify candidate pathways that may account for the comorbid constellation of symptoms. 
 Question: Willis-Ekbom disease is also known as?

Answer: restless legs syndrome


Question: Context: Coming off their home win over the Rams, the Bengals flew to Bill Walsh Field at Monster Park for a Saturday night interconference duel with the San Francisco 49ers. After a scoreless first quarter, Cincinnati trailed early in the second quarter as 49ers QB Shaun Hill got a 3-yard TD run. Afterwards, the Bengals would take the lead as kicker Shayne Graham managed to get a 24-yard field goal, while QB Carson Palmer completed a 52-yard TD pass to WR Chris Henry. San Francisco would end the half with Hill completing a 17-yard TD pass to TE Vernon Davis. In the third quarter, the 49ers increased their lead with kicker Joe Nedney getting a 29-yard and a 38-yard field goal. In the fourth quarter, Cincinnati tried to respond as Graham kicked a 35-yard field goal. However, the 49ers' defense held on for the win. With the loss, the Bengals fell to 5-9, securing Head Coach Marvin Lewis' first losing season with Cincinnati. 
 Question: Who is the Bengals quarterback?

Answer:
carson palmer