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.

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?
vestibular schwannoma

Context: Campers Gene and Marie Marsden took pride in being good citizens when in the wild. While driving miles to the Green River Lakes area, they taught their children what they had learned in the bear safety handbook put out by the Bridger-Teton Forest Service. Mr. and Mrs. Marsden did their best to keep a tidy camp. As the handbook had said to hang all food at least ten feet off the ground and four feet out from the trees, they did that and locked their food in their trailer at night. It was already dark when they went to bed, but they _ the campsite with flashlights, making sure nothing was left out. Following the bear book's advice, they slept a hundred yards from where they cooked their food, and kept the car near their tents, separated from the trailer, which they left up at the other camp. The Marsdens liked having their dog Spike on guard. But on the first night, Spike would not stop barking. When Marie Marsden pulled the tent open and shone her flashlight, she saw a young bear. They all piled into the car and drove quickly down the path, calling out of the window to Spike and abandoning the trailer. They drove to a pay phone and called a Fish and Game Department guard, who identified the bear by the white ring of the fur the Marsdens had seen around his neck. The authorities informed the Marsdens that the bear was a young male that they'd been keeping an eye on. The next morning, the Marsdens heard helicopters circling over the mountain and wondered if it might have something to do with the bear. After spending the night in the public campground, they drove back to their site. Wandering the area in search of clues, Marie came to a stop below a tall tree. She slapped her head and shouted, "Oh no!" "What is it?" Gene asked. Marie pointed at the ground where Spike's dog food bowl lay upside down. A week after their return home, the Marsdens read the headline in their local paper. "Bear Killed in Wind Rivers." According to the article, the Fish and Game Department had shot the young bear because, having been rewarded for invading a human campsite, it would likely to do so again. The Marsdens knew they had been lucky in the encounter, yet much to their shame and sadness, they also knew that the bear had not. 
 Question: Who is mostly to blame for the bear's death according to the writer?
the marsdens.

Context: The Musee du Pantheon National Haitien was opened in 1983. 
 Question: When was Musee du Pantheon National Haitien opened officially?

1983