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.

Input: Consider Input: Context: A physical change in matter is a change in one or more of matters physical properties. Glass breaking is just one example of a physical change. Some other examples are shown in Figure 3.16 and in the video below. In each example, matter may look different after the change occurs, but its still the same substance with the same chemical properties. For example, smaller pieces of wood have the ability to burn just as larger logs do. MEDIA Click image to the left or use the URL below. URL: Because the type of matter remains the same with physical changes, the changes are often easy to undo. For example, braided hair can be unbraided again. Melted chocolate can be put in a fridge to re-harden. Dissolving salt in water is also a physical change. How do you think you could undo it? Did you ever make a "volcano," like the one in Figure 3.17, using baking soda and vinegar? What happens when the two substances combine? They produce an eruption of foamy bubbles. This happens because of a chemical change. A chemical change occurs when matter changes chemically into an entirely different substance with different chemical properties. When vinegar and baking soda combine, they form carbon dioxide, a gas that causes the bubbles. Its the same gas that gives soft drinks their fizz. Not all chemical changes are as dramatic as this "volcano." Some are slower and less obvious. Figure 3.18 and the video below show other examples of chemical changes. MEDIA Click image to the left or use the URL below. URL: How can you tell whether a chemical change has occurred? Often, there are clues. Several are demonstrated in Figures 3.17 and 3.18 and in the video below. MEDIA Click image to the left or use the URL below. URL: To decide whether a chemical change has occurred, look for these signs: Gas bubbles are released. (Example: Baking soda and vinegar mix and produce bubbles.) Something changes color. (Example: Leaves turn from green to other colors.) An odor is produced. (Example: Logs burn and smell smoky.) A solid comes out of a solution. (Example: Eggs cook and a white solid comes out of the clear liquid part of the egg.) Because chemical changes produce new substances, they often cannot be undone. For example, you cant change a fried egg back to a raw egg. Some chemical changes can be reversed, but only by other chemical changes. For example, to undo the tarnish on copper pennies, you can place them in vinegar. The acid in the vinegar reacts with the tarnish. This is a chemical change that makes the pennies bright and shiny again. You can try this yourself at home to see how well it works. If you build a campfire, like the one in Figure 3.19, you start with a large stack of sticks and logs. As the fire burns, the stack slowly shrinks. By the end of the evening, all thats left is a small pile of ashes. What happened to the matter that you started with? Was it destroyed by the flames? It may seem that way, but in fact, the same amount of matter still exists. The wood changed not only to ashes but also to carbon dioxide, water vapor, and other gases. The gases floated off into the air, leaving behind just the ashes. Assume you had measured the mass of the wood before you burned it. Assume you had also trapped the gases released by the burning wood and measured their mass and the mass of the ashes. What would you find? The ashes and gases combined have the same mass as the wood you started with. This example illustrates the law of conservation of mass. The law states that matter cannot be created or destroyed. Even when matter goes through physical or chemical changes, the total mass of matter always remains the same. (In the chapter Nuclear Chemistry, you will learn about nuclear reactions, in which mass is converted into energy. But other than that, the law of conservation of mass holds 
 Question: After a physical change, matter may

Output: look different.


Input: Consider Input: Context: Dabigatran is a direct thrombin inhibitor used to reduce the risk of stroke in patients with nonvalvular atrial fibrillation. For patients who present with an acute stroke despite dabigatran therapy, clinical data on the use of intravenous tissue plasminogen activator (IV-tPA) is limited. There is an anticipated increased risk of symptomatic intracranial hemorrhage (sICH) when using IV-tPA in patients on dabigatran therapy. In 2015, the humanized monoclonal antibody fragment idarucizumab was approved for rapid (minutes) reversal of anticoagulant effects of dabigatran. Dabigatran reversal with idarucizumab before administration of IV-tPA might reduce the risk of sICH. We report a case of a 69-year-old stroke patient on dabigatran for paroxysmal atrial fibrillation who presented with an initial National Institutes of Health Stroke Scale (NIHSS) of 12. There was no early evidence of ischemic stroke or hemorrhage on head computed tomography, and coagulation studies implied therapeutic dabigatran levels. After controlling blood pressure, dabigatran was reversed with idarucizumab, and IV-tPA was administrated beginning 197minutes after he was last seen at his baseline. Subsequent brain magnetic resonance imaging showed 2 punctate infarcts in the left temporal lobe and occipital lobe with no evidence of hemorrhage. The patient was discharged with an NIHSS of 1. Telephone follow-up 2 months later indicated that he was at his prestroke baseline, except for a complaint of worsened short-term memory. Idarucizumab reversal of dabigatran may reduce the risk of sICH and should be considered for acute stroke patients arriving in the IV-tPA time window. 
 Question: Which drug can be reversed with idarucizumab?

Output: dabigatran


Input: Consider Input: Context: German academics believe they have solved the centuries-old mystery of the "Mona Lisa" in Leonardo ad Vinci's famous portrait . Lisa Gherardini, the wife of a wealthy Florentine merchant, Francesco del Giocondo, has long been seen as the most likely model for the sixteenth-century painting. Art historians have wondered whether the smiling woman may actually have been da Vinci's lover or mother, or the artist himself. Now experts at the prefix = st1 /HeidelbergUniversitylibrary say old notes made in a book by its owner in October, 1503, confirm that Lisa del Giocondo was indeed the model for the famous portrait in the world. "All doubts about the identity of the Mona Lisa have been removed by a discovery by Dr. Armin Schlechter," the library said in a statement on Monday. "Until then, only 'scant evidence' from sixteenth-century documents had been available. These had left lots of room for doubt, and many different identities were put forward." The comments compare Leonardo to the ancient Greek artist Apelles, and say he was working on three paintings at that time, one of which was a portrait of Lisa del Giocondo. Art experts say the Heidelbergdiscovery is a break-through, and the earliest mention linking the merchant's wife to the portrait. Before this discovery the earliest link dated from around 1550, and was made by Italian official Giorgio Vasari, the library said, adding that there had been doubts about Vasari's reliability. The Heidelbergnotes were actually discovered over two year's ago in the library by Schlechter, a spokeswoman said. Although the findings were published in the library's catalogue, they were not widely publicized, and received little attention until a German broadcaster decided to do some recording there, she said. 
 Question: Who discovered the Heidelbergnotes?


Output: dr. armin schlechter.