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.

Ex Input:
Context: Officials in the Midwestern U. S. town of Joplin, Missouri, say the death from Sundays' big tornado reaches 116 and that search efforts continue for possible survivors trapped in rubble . Search and rescue teams are conducting their third sweep through the nearly 10 kilometer - long and one - kilometer wide area of destruction left by the tornado. They are working as quickly as possible while weather conditions remain relatively stable. More storms are forecast for the area. Joplin Fire Chief Mitch Randles said there are areas with large piles of rubble that might hold survivors. "We are still finding individuals. We did rescue seven individuals from underneath rubble yesterday and, of course, we are also finding dead folks as well." Said more folks and that is why we are doing these searches. We want to make every opportunity that we can to find everybody that is in the rubble and that has survived to this point." Randles said the current sweep involves a slower pace that previous searches and that he plans a fourth search, possibly on Wednesday, using specially trained dogs. "We are searching every structure that has been damaged or destroyed in a more in-depth manner, "he said." I have dogs and dog handlers coming from all over the country do help us in that effort." Joplin City Manager Mark Rohr said the Red Cross and other volunteer organizations are helping people who were left homeless by the tornado and that the Federal Emergency Management Agency, or FEMA, is on hand to help. "Joplin is a great city. We have suffered a great loss, "said Rohr." We will recover and we will recover strongly and we have a lot of help and a lot of volunteers to make that easier." The tornado that struck Joplin was classified by the Natioonal Weather Service as an F - 4, with winds of more than 300 kilometers per hour. It lasted only 20 minutes, but it killed more that 100 people, injured more than 400 others, and destroyed or heavily damaged some 2,000 homes, businesses, churches and a hospital. Authorities have registered more than 1,700 calls about missing people and they hope to _ most of those cases soon, as victims are identified and survivors come forth and reunite with loved ones. This was the worst tornado to strike the United States in 60 years. It was the latest in a wave of violent storms that have swept Midwestern and southern states in recent weeks, leaving more than 300 people dead an causing more than $2 billion dollars in damage. 
 Question: What kind of disaster of this article is talking about?

Ex Output:
tornado


Ex Input:
Context: One of the primary criticismes of vestibular schwannoma (VS) radiosurgery is that the risk of surgical morbidity is increased for patients whose tumor progresses after the procedures. We reviewed the French experience of operated patients after failed Gamma Knife radiosurgery. From July 1992 to January 2002, 25 out of the 1000 treated patients underwent another treatment procedure for a gamma knife failure. Excluding the NF2 patients, 21 patients have been operated and the present study shows the data collected for 20 of them. In order to analyze the difficulties observed during the surgery, a questionnaire was filled by the surgeons. The mean interval between radiosurgery and removal was 36 Months, from 10 to 83 Months. The mean increase in Volume was 559% (37 to 3036%, median 160%). Evolution of the Koos grading was found from 8 grade II, 10 grade III et 2 grade IV to 10 grade III and 10 grade IV. Patients have been operated for radiological tumor growth in 7 cases and for clinico-radiological evolution in 13 cases. In 9 cases, the surgeon considered that he had to face unusual difficulties mainly because of adhesion of the tumor to neurovascular structures. Tumor removal was total in 14 cases, near total in 4 cases and subtotal in 2 cases. One case of venous infarction was noticed at the second day following surgery responsible of hemiparesis and aphasia that gradually recovered. At last follow-up examination, facial nerve was normal (House and Brackmann grade I and II) in 10 cases while it was a grade III in 7 cases and grade IV and V in 3 cases. We recommend that the decision for surgical removal of growing vestibular schwannoma after Gamma Knife treatment should be done after a sufficiently long follow-up period. Our results show that the quality of removal and of facial nerve preservation might be impaired by radiosurgery in half of cases. However these results do not support a change in our policy of radiosurgical treatment of small to medium size vestibular schwannoma. 
 Question: Which disease can be categorized using the Koos grading system?

Ex Output:
vestibular schwannoma


Ex Input:
Context: Patisiran is an investigational RNA interference (RNAi) therapeutic in development for the treatment of hereditary ATTR (hATTR) amyloidosis, a progressive disease associated with significant disability, morbidity, and mortality. Here we describe the rationale and design of the Phase 3 APOLLO study, a randomized, double-blind, placebo-controlled, global study to evaluate the efficacy and safety of patisiran in patients with hATTR amyloidosis with polyneuropathy. Eligible patients are 18-85years old with hATTR amyloidosis, investigator-estimated survival of 2years, Neuropathy Impairment Score (NIS) of 5-130, and polyneuropathy disability scoreIIIb. Patients are randomized 2:1 to receive either intravenous patisiran 0.3mg/kg or placebo once every 3weeks. The primary objective is to determine the efficacy of patisiran at 18months based on the difference in the change in modified NIS+7 (a composite measure of motor strength, sensation, reflexes, nerve conduction, and autonomic function) between the patisiran and placebo groups. Secondary objectives are to evaluate the effect of patisiran on Norfolk-Diabetic Neuropathy quality of life questionnaire score, nutritional status (as evaluated by modified body mass index), motor function (as measured by NIS-weakness and timed 10-m walk test), and autonomic symptoms (as measured by the Composite Autonomic Symptom Score-31 questionnaire). Exploratory objectives include assessment of cardiac function and pathologic evaluation to assess nerve fiber innervation and amyloid burden. Safety of patisiran will be assessed throughout the study. APOLLO represents the largest randomized, Phase 3 study to date in patients with hATTR amyloidosis, with endpoints that capture the multisystemic nature of this disease. This trial is registered at clinicaltrials.gov ( NCT01960348 ); October 9, 2013. 
 Question: What is the name of the RNAi investigational drug being developed against hereditary amyloidosis?

Ex Output:

patisiran