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: Neural stem/progenitor cells (NSCs) reside in the subventricular zone (SVZ) and subgranular zone of the hippocampal dentate gyrus in adult mammals. The ubiquitin ligase HRD1 is associated with degradation of amyloid precursor protein and believed to be specifically expressed in neurons and not in astrocytes. We investigated expression of HRD1 using immunohistochemistry and found colocalization of HRD1 with the NSC marker protein nestin and glial fibrillary acidic protein in the NSCs of the SVZ (the SVZ astrocytes) but not in the hippocampus. In the hippocampal dentate gyrus, HRD1 is localized in the nucleus of nestin-positive cells. 
 Question: Which intermediate filament (IF) protein can be used as a non-specific marker of the neuronal precursor cells of the subventricular zone?

Output: nestin


Input: Consider Input: Context: The immune system usually protects you from pathogens and other causes of disease. When the immune system is working properly, it keeps you from getting sick. But the immune system is like any other system of the body. It can break down or develop diseases. AIDS is an infectious disease of the immune system caused by a virus. Some diseases of the immune system are noninfectious. They include autoimmune diseases and allergies. Does it make sense for an immune system to attack the cells it is meant to protect? No, but an immune system that does not function properly will attack its own cells. An autoimmune disease is a disease in which the immune system attacks the bodys own cells. One example is type 1 diabetes. In this disease, the immune system attacks cells of the pancreas. Other examples are multiple sclerosis and rheumatoid arthritis. In multiple sclerosis, the immune system attacks nerve cells. This causes weakness and pain. In rheumatoid arthritis, the immune system attacks the cells of joints. This causes joint damage and pain. Autoimmune diseases cannot be cured. But they can be helped with medicines that weaken the immune systems attack on normal cells. Other autoimmune diseases include celiac disease (damages to the small intestine), inflam- matory bowel disease (damage to the digestive tract), psoriasis (damage to the skin), and lupus (damage to the joints, skin, kidneys, heart, and lungs). An allergy occurs when the immune system attacks a harmless substance that enters the body from the outside. A substance that causes an allergy is called an allergen. It is the immune system, not the allergen, that causes the symptoms of an allergy. Did you ever hear of hay fever? Its not really a fever at all. Its an allergy to plant pollens. People with this type of allergy have symptoms such as watery eyes, sneezing, and a runny nose. A common cause of hay fever is the pollen of ragweed. Many people are also allergic to poison ivy ( Figure 1.2). Skin contact with poison ivy leads to an itchy rash in people who are allergic to the plant. Ragweed is a common roadside weed found throughout the United States. Many people are allergic to its pollen. Some people are allergic to certain foods. Nuts and shellfish are common causes of food allergies. Other common causes of allergies include: Drugs, such as penicillin. Mold. Dust. The dead skin cells of dogs and cats, called dander. Stings of wasps and bees. Most allergies can be treated with medicines. Medicines used to treat allergies include antihistamines and corticos- teroids. These medicines help control the immune system when it attacks an allergen. Sometimes, allergies cause severe symptoms, a condition known as anaphylaxis. For example, they may cause the throat to swell so it is hard to breathe. Severe allergies may be life threatening. They require emergency medical care. 
 Question: autoimmune diseases can be cured with

Output: autoimmune diseases cannot be cured.


Input: Consider Input: Context: A pulley is a simple machine that consists of a rope and grooved wheel. The rope fits into the groove in the wheel, and pulling on the rope turns the wheel. Pulleys are generally used to lift objects, especially heavy objects. The object lifted by a pulley is called the load. The force applied to the pulley is called the effort. Q: Can you guess what the pulley pictured above is used for? A: The pulley is used to lift heavy buckets full of water out of the well. Some pulleys are attached to a beam or other secure surface and remain fixed in place. They are called fixed pulleys. Other pulleys are attached to the object being moved and are moveable themselves. They are called moveable pulleys. Sometimes, fixed and moveable pulleys are used together. They make up a compound pulley. The three types of pulleys are compared in the Table 1.1. Q: Which type of pulley is the old pulley in the opening image? A: The old pulley is a single fixed pulley. It is securely attached to the beam above it. Type of Pulley How It Works Example Single fixed pul- ley Flagpole pulley No. of Rope Segments Pulling Up 1 Ideal Mechani- cal Advantage 1 Change Direction Force? yes Single moveable pulley Zip-line pulley 2 2 no Compound pulley (fixed & moveable pulleys) Crane pulley 2 2 varies in of The mechanical advantage of a simple machine such as a pulley is the factor by which the machine changes the force applied to it. The ideal mechanical advantage of a machine is its mechanical advantage in the absence of friction. All machines must overcome friction, so the ideal mechanical advantage is always somewhat greater than the actual mechanical advantage of the machine as it is used in the real world. In a pulley, the ideal mechanical advantage is equal to the number of rope segments pulling up on the object. The more rope segments that are helping to do the lifting work, the less force that is needed for the job. Look at the table of types of pulleys. It gives the ideal mechanical advantage of each type. In the single fixed pulley, only one rope segment pulls up on the load, so the ideal mechanical advantage is 1. In other words, this type of pulley doesnt increase the force that is applied to it. However, it does change the direction of the force. This allows you to use your weight to pull on one end of the rope and more easily raise the load attached to the other end. In the single moveable pulley, two rope segments pull up on the load, so the ideal mechanical advantage is 2. This type of pulley doesnt change the direction of the force applied to it, but it increases the force by a factor of 2. In a compound pulley, two or more rope segments pull up on the load, so the ideal mechanical advantage is 2 or greater than 2. This type of pulley may or may not change the direction of the force applied to itit depends on the number and arrangement of pulleysbut the increase in force may be great. Q: If a compound pulley has four rope segments pulling up on the load, by what factor does it multiply the force applied to the pulley? A: With four rope segments, the ideal mechanical advantage is 4. This means that the compound pulley multiplies the force applied to it by a factor of 4. For example if 400 Newtons of force were applied to the pulley, the pulley would apply 1600 Newtons of force to the load. 
 Question: which type(s) of pulley can have a mechanical advantage greater than 2?


Output: compound pulley