What is cataract surgery?

Indications and Procedures

Cataract surgery refers to the surgical removal of the lens from the eye, generally because of a decrease in vision or other visual complaints, such as difficulty with night vision, glare, or loss of contrast. The decision to undergo cataract surgery, however, depends most often on the individual’s subjective threshold for what constitutes unacceptable vision.

Every eye contains a lens that allows images to be focused on the retina, much like a camera focuses light. Over time, most people develop some degree of opacity in their lens, which can only be remedied by surgically removing the lens and replacing it with an artificial one. The artificial lens
can be made from a variety of materials, such as silicone, acrylic, or other biocompatible synthetic substances.

Because of the refinement in instrumentation and technique, general anesthesia is rarely indicated in cataract surgery, and the procedure is often performed on an outpatient basis. Anesthesia is generally administered by injection of the anesthetic solution around the eye or by placing anesthetic drops on the eye. The surgical approach to lens extraction depends to some extent on the nature of the cataract and the surgeon’s preference. The majority of surgeons use an ultrasound device to break the cataract into small fragments, which are then aspirated with the same device (phacoemulsification). This procedure is often performed through a very small incision, which may be left to close by itself or be closed with one small suture. Under certain circumstances, the ophthalmologist may elect to remove the entire lens in a single piece (extracapsular surgery), in which case a larger opening is needed into the eye to gain access to the cataract.

Once the cataract is removed, a clear artificial intraocular lens (IOL) is often placed in its position to allow the eye to continue to focus light properly. The IOL may be single focus (focusing at only one distance) or multifocal (focusing at both near and far distances). In general, cataract surgery is performed on one eye at a time, since a resulting infection in both eyes, albeit rare, can be quite devastating. The length of the procedure is often significantly less than one hour, provided there are no complications or special needs.

In most cases, the patient returns home the same day and may wear a patch over the eye until the next postoperative day, when he or she is seen on follow-up. The patient is then asked to start using a combination of antibiotic and anti-inflammatory agents to prevent infection and reduce inflammation. Alternatively, some surgeons recommend starting drops immediately following surgery in order to hasten recovery. Some ophthalmologists also suggest using these drops prior to surgery in order to minimize the risk of infection and inflammation even further. Visual recovery varies greatly among individuals and may be as short as a day or as long as several months.

Uses and Complications

Although cataracts are mostly a condition affecting the elderly, they can occur at any age and even in newborns. Cataracts may have various causes, although the most common is related to simple aging and does not necessarily reflect a significant disease of the eye or the body. The presence of cataracts in young children or young adults is never normal, however, and must be promptly addressed, especially in newborns. Potentially more serious conditions may mask themselves as cataracts in the young child. Therefore, unlike the adult cataract, the progression of which can be carefully followed over time, the cataract in the newborn must be quickly referred to an ophthalmologist for surgical care.

With the many refinements in technique and technology, the overall morbidity of this procedure has significantly diminished, and the majority of patients who undergo cataract surgery find it to be a positive life-altering experience. As with most surgical procedures, infection and bleeding can occur during cataract surgery. Although rare, a resulting eye infection, known as "endophthalmitis," can have devastating consequences and must be addressed immediately. The signs and symptoms of endophthalmitis include decreased vision, pain, and redness. A more common complication of surgery is swelling of the retina (macular edema). This condition may lead to suboptimal vision following surgery but can generally be treated with anti-inflammatory drops. Finally, one or more fragments of the lens may become dislodged in the eye as a result of a rupture of the capsule surrounding the cataract. If the surgeon deems it unsafe to proceed further, then the eye may be closed and approached at a later time with the help of a retinal surgeon, who can then safely remove any remaining fragments from the eye. It is not uncommon for a secondary cataract to form on the implanted IOL; this is treated using a laser technique called "posterior capsulotomy." Other rare but potential complications include the loss of the clarity of the cornea, retinal detachment, glaucoma, or long-standing inflammation.

Perspective and Prospects

The word “cataract” is derived from a Greek and Latin word meaning “waterfall,” referring to the visible veil that forms in the pupil. Cataracts constitute the most common cause of preventive blindness throughout the world. In 2010, close to twenty million people around the world were blind as a result of cataracts. No medicinal treatments are currently available for cataracts. There is some evidence that a healthy lifestyle with proper precaution against ultraviolet (UV) light can slow the formation or progression of cataracts.

Future trends in the management of cataracts point to less invasive surgical approaches, with smaller incisions and devices that produce less collateral heat. Laser devices for cataract surgery continue to improve and may one day equal or surpass ultrasound devices in their ability to address most cataracts safely.

Significant progress continues to be made in the realm of artificial intraocular lenses. Many IOLs can now be folded or injected into the eye through very small incisions. Some progress has been made to manufacture lenses that provide true accommodation, much like a young individual’s eyes, thus obviating the need for reading glasses. Finally, with the advent of better antibiotic solutions, the potential risk of infection is significantly reduced.

Bibliography

A.D.A.M. Medical Encyclopedia. "Cataract Removal." MedlinePlus, September 14, 2011.

Albert, Daniel M. Ophthalmic Surgery: Principles and Techniques. 2 vols. Malden, Mass.: Blackwell Science, 1999.

Buettner, Helmut, ed. Mayo Clinic on Vision and Eye Health: Practical Answers on Glaucoma, Cataracts, Macular Degeneration, and Other Conditions. Rochester, Minn.: Mayo Foundation for Medical Education and Research, 2002.

Cheyer, Christopher, ed. "Cataract Removal."Health Library, February 28, 2012.

Eye Smart. "Cataract Surgery."American Academy of Ophthalmology, 2013.

Gottsch, John D., Walter J. Stark, and Morton F. Goldberg, eds. Ophthalmic Surgery. 5th ed. New York: Oxford University Press, 1999.

Houseman, William. “The Day the Light Returned.” New Choices for Retirement Living 32 (April, 1992): 54–58.

Parker, James N., and Philip M. Parker, eds. The Official Patient’s Sourcebook on Cataract Surgery. Rev. and updated ed. San Diego, Calif.: Icon Health, 2005.

"Prevention of Blindness and Visual Impairment: Priority Eye Diseases—Cataract." World Health Organization, 2013.

Shulman, Julius. Cataracts—From Diagnosis to Recovery: The Complete Guide for Patients and Families. Rev. ed. New York: St. Martin’s Griffin, 1995.

Spaeth, George L., ed. Ophthalmic Surgery: Principles and Practice. 4th ed. Philadelphia: W. B. Saunders, 2012.

Sutton, Amy L., ed. Eye Care Sourcebook: Basic Consumer Health Information About Eye Care and Eye Disorders. 3d ed. Detroit, Mich.: Omnigraphics, 2008.

A country singer made 2,000 for his last show. He enjoys boots and hats. Each pair of boots costs 100 and each hat costs 50. What is the best...

Hello!

As I understand, a singer is going to spend all that 2000 for boots and hats. If we denote the number of boots pairs as b and the number of hats as h, then we obtain a linear inequality

100b + 50h <= 2000, or 2b + h <= 40.

Also of course 0 <= b <= 2000/100 = 20 and 0 <= h <= 2000/50 = 40. These inequalities describe the triangle with the vertices (0, 0), (20, 0) and (0, 40) on the (b, h) plane.

Unfortunately, you didn't give any additional  conditions to choose what combination is better for a singer. If he wants a maximum number of kits (a hat + a pair of boots), then he can buy a maximum of 13 kits and 50($) remains so he can by one more hat.

Do you believe that Lee Harvey Oswald acted alone, or was involved at all in the assassination of John F. Kennedy or do you think JFK's death was...

I think Lee Harvey Oswald acted alone. First, the Warren Commission decided Oswald carried out the assassination alone and that there was no conspiracy. The 888-page report, concluded in 1964, demonstrated that the same bullets used to kill Kennedy came from the model of rifle Oswald used. Oswald was a trained military sharpshooter, so firing three shots in three seconds from a bolt-action rifle would not have been impossible. Oswald worked in the Texas Book Depository, so it would not have been suspicious for him to be there during the parade. Also, the Zapruder film, upon recent digital analysis, shows Oswald in the Depository at the window from where the shots were fired.  

While it is popular to believe the Soviets, Castro, or the CIA were parties to the assassination, there has not been any conclusive evidence to prove Kennedy was killed by any of these groups. The only bullets recovered from the crime scene were from Oswald's cheap mail-order rifle. Oswald had the expertise to fire the shots. Since there is no other convincing evidence, one has to go with the findings of the Warren Commission and declare Oswald the most likely shooter.

Compare Plautus A Pot of Gold and Plautus The Haunted House are they similar or different?

Plautus, as well as almost every other writer who has ever penned a word, produces work that is then categorized by other people in the world of literature. The same is true of Homer, Pliny, Milton, Shakespeare and others.

In the process of this categorization, or sorting, one runs across examples such as the two about which you have enquired: The Pot of Gold, and The Haunted House.

After an initial reading of the two they seem to be similar in some ways. The element of subterfuge, the potential for trouble, the potential for good, the confusion of the characters are all examples of these similarities.

The main difference is the mood and the subject. The have a different "feel" that makes the reader assume that they are totally different types of writing. The Pot of Gold contains one of the most hilarious scenes in ancient writing, while The Haunted House has a different atmosphere.

So that when the main similarity - that they are both categorized as "Comedies" - is seen, it can be a bit confusing.

My advice would be to look more deeply into the literary and theatrical definitions of "Comedy" to continue your comparison. I believe it will help

What parts of Romeo and Juliet show passion to be unpredictable? Please provide quotes.

The passion with which Mercutio spins his tale of Queen Mab could be considered unpredictable. At first it seems as though he is just making up a funny story about a fairy who makes men dream. The audience may think Mercutio is simply trying to amuse his friends, but then his storytelling takes a dark turn as he delves into violence and sexual innuendo. The story is initially harmless and light hearted:

She is the fairies’ midwife, and she comes
In shape no bigger than an agate stone
On the forefinger of an alderman

From line 58 to line 86 of Act I, Scene 4, Mercutio's speech is without tension but then an unpredictable passion seems to overtake him at line 87. What had been a story about a fairy and lovers takes on an edginess with references to "cutting foreign throats" and then to brutal sexuality in the last few lines:

This is the hag, when maids lie on their backs,
That presses them and learns them first to bear,
Making them women of good carriage.

Mercutio displays more emotion at the end of his speech and works himself into quite a fit, so much so that Romeo has to quiet him:

Peace, peace, Mercutio, peace.
Thou talk’st of nothing.

Another possible example of unpredictable passion occurs in Act III, Scene 5 when Lord Capulet totally changes his mind about Juliet marrying Count Paris and bursts into a rage when his daughter goes against him. Prior to this scene, Capulet had shown a good deal of humility and common sense. When Paris first asks to marry Juliet, Capulet thinks only of his daughter's welfare, telling Paris to first win Juliet's love. Again in Act I, Scene 5 he is the voice of reason when Tybalt wants to fight Romeo during the party. Capulet even speaks well of Romeo:

Verona brags of him 

To be a virtuous and well-governed youth).

In Act III, however, he displays a much different attitude. When Lady Capulet informs him that Juliet is not willing to marry Paris he goes berserk, showing a passion that the audience had not seen before:

How, how, how, how? Chopped logic? What is this?
“Proud,” and “I thank you,” and “I thank you not,”
And yet “not proud”? Mistress minion you,
Thank me no thankings, nor proud me no prouds,
But fettle your fine joints ’gainst Thursday next
To go with Paris to Saint Peter’s Church,
Or I will drag thee on a hurdle thither.
Out, you green-sickness carrion! Out, you baggage!
You tallow face!

Capulet eventually threatens to disown Juliet and kick her out of the house. This is a different man from the one who urged the Count to "woo her, gentle Paris, get her heart."

Other displays of unbridled passion are predictable. Tybalt's aggressiveness, Romeo's infatuation with Rosaline and then Juliet, Mercutio's reaction to Tybalt's insults and even Juliet's impatience with the Nurse seem normal reactions given the circumstances.

What is celiac sprue?

Causes and Symptoms

The most common symptoms of celiac sprue are diarrhea and weight loss. Patients develop an inflammatory reaction to gluten, a protein found in wheat, rye, oats, and barley. This inflammation causes flattening of the fingerlike projections in the small intestine known as "villi," thereby decreasing the surface area available for nutrient and fluid absorption. Thus, patients often have anemia (from malabsorption
of iron and folic acid) and bone disease (from malabsorption of calcium and vitamin D). Other symptoms of celiac sprue can include muscle weakness, infertility, epilepsy, and psychiatric illnesses, although the mechanisms underlying these manifestations are less clear. Some patients develop a blistering, itching
rash on the skin known as "dermatitis herpetiformis." Most patients come to medical attention at two years of age, after wheat is introduced into the diet. A small number of people develop the disease as adults. Research suggests that stress can trigger celiac sprue reactions, including extreme emotional stress, pregnancy, surgery, and infections.

Treatment and Therapy

The mainstay of therapy is elimination of gluten from the diet, which calms the inflammation and eventually allows the flattened villi to grow back. Symptoms usually improve within two weeks. Lack of improvement is most often the result of incomplete elimination of gluten. Alternative diagnoses—including infection, food allergies, inflammatory bowel disease, and lymphoma of the intestines—must also be considered.

The avoidance of gluten sounds straightforward, but it often requires significant dietary changes that must be rigorously followed throughout life. Most breads, pastas, and pastries must be avoided. Patients often benefit from counseling with a dietitian, since many processed foods contain gluten. Patients may also need to be screened for vitamin and mineral deficiencies. Folic acid supplementation is especially important for women of childbearing age. An x-ray to determine bone mineral density is sometimes helpful in patients with suspected vitamin D deficiency.

Perspective and Prospects

Celiac sprue is a genetic disease. It is known to be caused by a mutation on chromosome 6, and attempts to identify the specific gene further are ongoing. Testing to determine whether one has celiac sprue includes blood tests for antibodies against gliadin, the offensive component of gluten. About 1 percent of the global population suffers from celiac sprue. People at higher risk for celiac sprue include those who have diabetes mellitus, an autoimmune disease, Down syndrome, or anemia and those with a family member who has celiac sprue.

Bibliography

A.D.A.M. Medical Encyclopedia. "Celiac Disease." MedlinePlus, January 20, 2010.

Green, Peter H. R., and Rory Jones. Celiac Disease: A Hidden Epidemic. Rev. ed. New York: William R. Morrow, 2010.

Holmes, Geoffrey, C. Catassi, and Alessio Fasano. Celiac Disease. Abingdon, England: Health Press, 2009.

Korn, Danna. Kids with Celiac Disease: A Family Guide to Raising Happy, Healthy, Gluten-Free Children. Bethesda, Md.: Woodbine House, 2001.

Mahadov, Srihari, and Peter H. R. Green. "Celiac Disease: A Challenge for All Physicians." Gastroenterology & Hepatology 7, no. 8 (August, 2011): 554–556.

Parker, James N., and Philip M. Parker, eds. The Official Patient’s Sourcebook on Celiac Disease. San Diego, Calif.: Icon Health, 2002.

Shepard, Jules E. Dowler. The First Year: Celiac Disease and Living Gluten-Free—An Essential Guide for the Newly Diagnosed. Cambridge, Mass.: Da Capo Lifelong, 2009.

Tessmer, Kimberly A. Gluten-Free for a Healthy Life: Nutritional Advice and Recipes for Those Suffering from Celiac Disease and Other Gluten-Related Disorders. Franklin Lakes, N.J.: New Page Books, 2003.

Wood, Debra, and Daus Mahnke." Celiac Disease." Health Library, January 28, 2013.

What do we see first--color or shapes?

Your question can be interpreted two different ways, but the answer is the same for both--shapes can be seen before color. Your question could either be referring to what can be seen first as an infant's vision develops, or as to what people can see as light slowly increases from darkness.

Infants can distinguish shapes soon after they are born, with a limited range in which they can focus (between about 8 and 12 inches from their eyes). Babies can see the color red when they a few weeks old, with a full range of color vision by the age of about 5 months.

For vision in slowly increasing light, shapes are visible first. There are two types of receptors in the retina, rods and cones. Rods sense black and white differences, and can detect shapes in relatively low light. Cones are for color vision, and require more total light to function. You can test this yourself if you get up before dawn one morning. You will see black, white and gray shapes at first, and gradually will see colors as the sun comes up.

Identify a current issue of national or international concern. What are the effects of this issue on the U.S.?

One of the most public and important issues facing the United States and all of the Western world is the rise of Islamic extremism and the terrorist attacks performed by the Islamic State of Iraq and the Levant (a collection of Middle Eastern or eastern Mediterranean countries). This group is more commonly known as ISIS or ISIL.

This issue has numerous effects on the Unites States. Let's examine two:

1. Boots on the Ground Operations: The United States is consistently at war with ISIS. This war is fought, in part, through airstrikes by drones. But it also requires American soldiers to be deployed to the Middle East. Even just this month, March 2016, more soldiers are being deployed in the wake of a rocket attack on United States marines.

These soldiers are being deployed just a few short years after the United States unsuccessfully tried to withdraw troops from another Middle Eastern conflict. The sheer manpower that the United States has employed in that region of the world is a drain on resources and, more importantly, a drain on the families of those servicemen and women.   

2. Culture War: This conflict is not just a military engagement, however. The continued violence between the West and the Islamic State is a literal clash of cultures. In his famous essay-turned-book, Sam Huntington argued that "dangerous clashes...are likely to arise from the interaction of Western arrogance, [and] Islamic intolerance" (Huntington, The Clash of Civilizations, 1996).  

Western culture and Islamic culture seem to many fundamentally incompatible. One is democratic and celebrates the separation of church and state (theoretically), while the other is fascist and theocratic. The existence of one of these cultures is a threat to the other. 

How was the South affected by the Civil War?

The South was affected by the Civil War in many ways. One way was that slavery and all that slavery represented came to an end. This required the South to free the slaves and live in a society where nobody owned another person. The former slaves now had rights they never had before. These changes were dramatic for the South. Since the beginning of our country, many people in the South believed in the superiority of the white race. They were used to controlling the African-Americans and having many of them work as slaves without having any rights or freedoms.

Another way the South was affected by the Civil War was that there was complete destruction in the South. Towards the end of the war, the North waged total war on the South, destroying everything in the path of the Union army. Also, since most of the fighting in the Civil War was done in the South, there was much damage to the land and to property. As a result, the South had to be rebuilt after the Civil War ended. This led to a diversification of the southern economy as more industries were built in the South.

The South also had to reject their belief in states’ rights and in nullification. The South strongly believed that states should have the right to reject laws that hurt them. After the Civil War ended, the southern states had to write new constitutions that rejected the concept of nullification as a condition of being readmitted to the Union. 

The Civil War had a tremendous impact on the South.

In That Was Then, This Is Now by S. E. Hinton, what created a strain in the formally friendly relationship between Mark and Cathy?

In Chapter 6, Bryon, Cathy, Mark, and M&M go for a drive down the Ribbon and hang out together. While they are sitting at a red light, a person in the car to the left of them makes an obscene gesture and a rude comment. Mark then reaches across M&M, opens the door, runs over to the car, and punches the person in the face. After Mark had hopped back into the car, Bryon drives off. Cathy then makes a sarcastic comment by saying, "You're a fast worker" (Hinton 97). Mark responds by saying that he gets these "impulses," to which Cathy dryly says, "Impulses to jump out of cars and hit people?" (Hinton 97). Mark intelligently replies by saying "They hit us first...A hit don't have to be physical. I couldn't hit them the way they hit us without hitting you, too" (Hinton 97). Bryon then mentions how surprised Cathy was at Mark's thoughtful answer. Cathy then comments that she never knows what to make of Mark, and Mark essentially tells her to lighten up and stop trying to analyze people.

Later on, they stop at a drive-in to grab something to eat, and Bryon begins to tell the story to Cathy about the time he was beaten up for being drunk. When Cathy tells Bryon that he shouldn't have been drinking, Bryon says, "I never thought of it that way" (Hinton 99). Mark then enters the conversation and says, "Who would?" (Hinton 99). Bryon mentions

"I realized right then that whatever chance Mark and Cathy had ever had of becoming friends was gone. I had already sensed in Cathy the same hostility toward Mark that he had for her" (Hinton 99).

Bryon is constantly spending time with Cathy instead of Mark, which initially creates a strain in their relationship. Mark had harbored feelings of jealousy for Cathy because she spent so much time with Bryon, but when Mark and Cathy hang out, his true personality conflicts with hers. Cathy is thoughtful and sensitive, while Mark is rash and violent. Cathy does not like Mark's attitude, and Mark cannot stand being judged. After Cathy realizes that Mark does not understand right from wrong, she begins to view him with contempt.

What is pharmacology?

Science and Profession

The science of pharmacology includes the history, source, physical and chemical
properties, and biochemical and physiological effects of drugs (therapeutic
chemicals, diagnostic chemicals, toxins, and related substances).

“Drug” is a noun in common usage, but it has complex meanings. “Drug” or
“medicine” is often used today to indicate a therapeutic substance usually
obtained from a pharmacy or drugstore. “Drug” also is used to indicate an illegal
substance used for mood-altering effects. Historically, people made their own
drugs from materials found naturally in plants, animals, and minerals; some people
continue to do so. The term “drug” in this article will focus on the meaning as it
is understood by scientists called pharmacologists. Any chemical can be thought of
as a drug by a pharmacologist: A drug is simply a chemical that produces a change
in a biological process.

Water and oxygen can be thought of as drugs, as can foods and poisons. “Drug,”
therefore, is a word to indicate an idea, concept, or perception about a chemical.
When the chemical, such as oxygen, is causing a change in a biological process,
then the chemical is acting as a drug. If the same chemical is causing a change in
some other kind of system—for example, causing an iron rod to rust—then the
chemical is not acting as a drug. Drugs may be found in nature or made by humans.
Most of the chemicals used today as drugs are made by humans.

The biological process that is being changed by a drug may be one occurring in a sick person. Many drugs are used therapeutically—that is, to treat diseases—but pharmacologists do not limit drugs to therapeutic chemicals. They are interested in drug effects on any biological process, even healthy ones occurring in plants and microorganisms, as well as those in animals and humans.

All drugs, even therapeutic drugs, have several effects on biological processes.
Some of these effects are seen only at high concentrations. Unwanted effects,
especially if they are injurious, are called adverse effects. A serious adverse
effect, especially if it requires special medical treatment, may be considered a
toxic reaction, or poisoning. Any chemical that produces
an injurious effect, one that is detrimental to a biological process, is called a
toxin. The severity of the toxic effect is based on the
concentration of the toxic substance. Toxic substances in the environment are
called pollutants.

The idea of drug concentration is very important. “Concentration” refers to the
number of chemical molecules in a specified volume (such as a teaspoonful, an
ounce, or a milliliter) of liquid or gas. Concentration is related to dosage and
to the intensity of a drug’s effect on a biological process. It is important to
remember, however, that the effect of a drug on the body may vary considerably
depending on the route of administration. For instance, if one were to eat a drug,
then metabolism of the drug is usually very slow, whereas if one were to inject a
drug into the bloodstream, then the effects of the drug are observed quite
rapidly. Therefore, when pharmacologists discuss drugs and their effects,
particularly on humans, they will also frequently discuss the route of
administration to make the context of the effect clear.

Concentration and the related concept of dilution are easy to understand. Two
spoonfuls of sugar in a glass of water form a more concentrated solution of
sugar-water than one spoonful of sugar. The more concentrated sugar-water will
taste sweeter. Since taste is a biological process caused by a chemical, the
chemical (sugar) can be thought of as a drug. The concentration of the chemical
affects the biological process. There is a limit, however, to the sweetness of a
solution. At some point, more sugar added to the solution will not increase the
sensation of sweetness. Adding more sugar may result in a “toxic” reaction of
nausea and even vomiting.

There are also different kinds of sugars. When one says that some are sweeter than
others, one means that sweeter sugars will be just as sweet at very dilute
concentrations as less-sweet sugars at very high concentrations. Thus the first
kind of sugar is said to be more potent than the second, even though the second
can be just as sweet at high concentrations. Some sugars, however, will not taste
very sweet regardless of the concentration. This example illustrates principles
that are shared by many drugs. It is important to understand that taking a double
dose of a drug will not necessarily produce a double effect. It is also important
to understand that a tiny dose of one drug can have the same, or even stronger,
biological effect than a large dose of a similar drug.

Most therapeutic drugs act directly on special parts of cells within the body
called receptors. A receptor is part of the cell structure. A
receptor for a specific drug is always located at the same place within a cell.
Yet there are different kinds of receptors found at various locations in cells.
Many receptors are found on the cell surface; others are found inside cells. Some
receptors are found only on certain types of cells.

Each type of receptor has a specific function. When a drug “fits” a receptor, like
how a key fits a lock, the receptor starts the biological process for which the
drug is known. Different kinds of drugs can fit a single type of receptor, which
explains why different drugs (for example, aspirin and acetaminophen) can have
similar effects (relieve pain). Furthermore, one drug may be able to act on
several different types of receptors. A receptor, however, can have only one
biological response to all the drugs that act on it.

A drug acting on receptors in cells of one organ can affect distant organs. For
example, a drug acting on brain cells may cause the nerves acting on blood vessels
to increase blood pressure, which can change the heartbeat. The effect of a drug
on receptors is usually temporary and should be reversible. In most cases in which
a drug works through a receptor, the receptor releases the drug after the two have
come together. If this release does not occur, the receptor is said to be blocked.
The blockage of a receptor can be therapeutically beneficial, but it may sometimes
lead to an adverse reaction.

In humans and animals, most drugs travel in the bloodstream to reach cell receptors. The drug enters the bloodstream after being applied to a body surface or after being swallowed, inhaled, or injected. The effect of the drug is eventually diminished because the body dilutes the drug, chemically alters it (so that it no longer has a pharmacological effect), and eliminates it. Chemical alteration of drugs usually occurs in the liver by a process called biotransformation. Elimination of most drugs, or their biotransformed relatives, usually occurs through the urine but may sometimes occur through secretions (sweat, tears, or breast milk), feces, or even exhaled gases.

Diagnostic and Treatment Techniques

Three examples of the use of therapeutic chemicals in the field of pharmacology are anesthesia, cardiac-enhancing drugs, and drugs that fight infections. These examples demonstrate the use of various classes of drugs and provide insight to the variety of drug action.

Anesthetics are chemical painkillers. They are very
important drugs, because most diseases are accompanied by pain. Often,
the first objective of a patient is to get relief from the pain, even though the
anesthetic may do nothing to cure the disease. Pain is a sensation felt in the
brain, not at the site of injury. Special nerves at the site of injury send a
signal (nerve impulse) to the brain, where it is interpreted as pain occurring at
a specific location in the body. Mild pain and severe pain are detected by
different kinds of nociceptive (pain-sensing) nerves. As pain increases in
severity, the brain not only perceives and interprets the pain but also sends out
special autonomic signals.

Autonomic signals from the brain serve an extremely important function: They
control body functions that do not require conscious thought, such as sweating,
heart rate, blood pressure, digestion, and eye focus. Autonomic signals coordinate
these functions and change them in response to conditions outside the body. When
the body is threatened, such as when a person is frightened, autonomic signals
prepare the body to fight or to flee the threatening situation. The pain of
surgery causes the brain to send autonomic signals to put the body in a defensive
state, resulting in sweating and increases in heart rate, breathing, and blood
pressure. Additionally, all the muscles of the body will become tense. This
defensive state is undesirable during surgery.

Drugs used to relieve pain without causing unconsciousness are called analgesics.
Mild pain can usually be controlled with an analgesic such as aspirin. More
severe pain may require an opioid analgesic such as morphine.
Sometimes, the term “narcotic” is used as a synonym for opioid analgesics, but
that term is often used in a legal context to indicate any chemical that can cause
dependence (addiction). An analgesic changes the way in
which the brain interprets a nociceptive stimulus. The most severe pain, such as
that during surgery, is controlled by an anesthetic. An anesthetic may act at a
specific site, such as on the nerves of a tooth; a local
anesthetic such as novocaine blocks the transmission of the
nociceptive stimulus to the brain. Other anesthetics, required for major surgery,
cause a loss of consciousness; these are called general anesthetics. As with all
therapeutic drugs, the action of an anesthetic is reversible.

A general anesthetic should perform several functions: It should alter the brain’s
interpretation of pain, cause a temporary amnesia that prevents remembrance of the
nociceptive sensation, produce autonomic stability, and cause muscle relaxation.
This is much to ask of a single drug. Therefore, general anesthesia is achieved by
using several drugs, each capable of accomplishing one or more of the goals.

A general anesthetic agent usually works on nerve cells to provide pain relief and amnesia. These general functions are provided by both kinds of general anesthetics, those that are inhaled and those that are injected. Other drugs are used to control autonomic signals and to provide for muscle relaxation. When the surgery is completed, the patient returns to consciousness as the anesthetic agents are removed from the nerves. This is done by biotransformation and by excretion. Pain immediately after surgery will be controlled by an opioid analgesic. When the pain diminishes as healing progresses, it becomes milder and can be controlled with a nonopioid analgesic.

Drugs are also important in helping people recover from a myocardial infarction
(heart
attack). The heart is a pump that supplies blood to all cells
of the body. Blood carries oxygen and nutrients to the cells and removes waste
materials from them. The heart is a living muscle composed of cells, and blood
vessels must supply each cell of the muscle. If a blood vessel in the heart
becomes suddenly blocked, then the cells served by that blood vessel become
starved and die. This is a heart attack. If only a small portion of the heart is
injured, the person can survive the attack, especially if drugs are given that
strengthen the heart.

An important class of drugs used to strengthen the heart is composed of the
cardiac glycosides, such as digitalis. These drugs act to improve the ability of
the heart cells to use calcium efficiently. Calcium is essential to maintaining a
normal heartbeat. Because a heart attack is painful, it causes a defensive
autonomic response from the brain. It is important to use analgesics to relieve
the pain and other drugs to control the autonomic response. Another important
therapy is to provide more oxygen to the heart. This is done directly, by
administering oxygen, but it is also done by using drugs that can remove the
blockage from the blood vessel. Since the blockage usually occurs when a blood
clot forms in a damaged blood vessel, drugs that dissolve clots can sometimes open
the blocked vessel and restore the flow of oxygen-rich blood to the starved cells.
A person recovering from a heart attack will sometimes be given drugs to prevent
another blockage. Some drugs prevent fatty deposits from forming in the vessels,
while others act to slow down clot formation.

Drugs used to treat infection are designed to kill cells. Infection is
caused by foreign microbes attacking the body. The microbes may be viruses,
bacteria, fungi, or even parasitic worms. Antimicrobial drugs (antibiotics) are
given to the infected person to destroy the foreign cells without damaging the
patient’s own cells. Therefore, the drug must be selectively toxic to the foreign
cells. Few drugs are perfectly selective, however, and most have some toxic
effects on the patient as well.

There are many ways to develop a selectively toxic drug, but selectivity usually
depends on a unique feature of the invading foreign cells, such as the cell walls
of bacteria. Human cells are surrounded by cell membranes. Bacteria have cell
membranes as well, but they also have cell walls outside these membranes. If the
bacterial cell
wall is damaged, then the bacterium becomes weakened and can
be killed by the body’s defense mechanisms. Penicillin is
an antibiotic drug that damages the cell walls of many bacteria. Penicillin has
few adverse effects on the infected person, because human cells do not have cell
walls. (Unfortunately, however, some people develop an allergic reaction to
penicillin.)

Perspective and Prospects

In the prehistoric world, priests were called upon to intercede for persons suffering from disease and pain. As humans gained experience and developed a means of sharing that experience, especially through written records, it was noticed that certain components of the diet could reliably inflict or relieve pain; these were the first drugs. Similar effects could be obtained by inhaling natural materials or applying them to the skin through rubbing or injection. Such activities were thought to involve supernatural powers, however, and authority to use these drugs was still restricted to members of the priesthood, namely, medicine men or shamans.

Writings about the medicinal properties of natural materials can be found in
Chinese, Egyptian, Greek, Indian, and Sumerian manuscripts, some of which are
thought to be as much as six thousand years old. The Ebers Papyrus of Egypt (1550
BCE) contains more than eight hundred prescriptions using seven hundred drugs. It
was known that some drugs were cathartics, some were diuretics, and others were
purgatives, soporifics, or poisons. Yet factual knowledge about why these actions
occurred was lacking, in large measure because knowledge of body function and
chemistry was lacking. In this absence, people speculated that drug action was due
to “essential properties” of the drug, such as warmth or wetness.

Only with the European Renaissance in the early sixteenth century was the
scientific
method applied to questions about the natural world, both
physical and living. In 1543, Andreas Vesalius published the first
complete description of human anatomy. In the early seventeenth century,
William
Harvey discovered the circulation of blood, and
Antoni van
Leeuwenhoek discovered living cells with his microscope. In
the eighteenth century, the chemistry of oxygen was established by
Carl
Scheele, Joseph Priestley, and Antoine
Lavoisier, and by the end of the century, chemical methods
were becoming available to separate pure drugs from crude natural concoctions. In
1806, Friedrich W. Serturner purified morphine from the opium poppy, and in 1856,
Friedrich
Wöhler isolated cocaine from coca. Also of great intellectual
and economic significance was the 1828 synthesis by Wöhler of urea, the first of
many chemicals which heretofore had been available only from living organisms.
Hormones, general anesthetics, and the bacterial cause of infectious diseases were
discovered.

Until the twentieth century, drugs were discovered empirically; they existed in
nature and needed to be “found.” The knowledge gained during the nineteenth
century about how drugs worked enabled pharmacologists of the twentieth century to
“design” drugs not found in nature. For example, Paul Ehrlich,
a German scientist, announced in 1910 that he had successfully combined a dye that
stains bacteria with the poison arsenic to create an antibacterial drug,
arsphenamine (Salvarsan), that is highly effective in treating syphilis. In a
similar way, the antibacterial sulfonamide chemicals were developed in the
1930s.

It was soon recognized that the powerful effect of pure drugs (in contrast to
potions made from natural materials) had the potential to harm as well as to help,
to kill or to cure. The safe use of these drugs required special knowledge, so
government agencies were established in the twentieth century to regulate drug
manufacture and distribution. The original Pure Food and Drug Act, passed by the
United States Congress in 1906, imposed quality controls on drug manufacturers. In
1927, Congress created the Food, Drug, and Insecticide Administration (FDIA), to
enforce the 1906 law. Until 1914, any drug could be obtained without a
prescription; this was changed by the Harrison Narcotic Act. Further limitations
on the sale of drugs to the general public came with the Food, Drug, and Cosmetic Act of
1938 and the Durham-Humphrey Amendment of 1951. The
Controlled
Substances Act of 1970 superseded the Harrison Narcotic
Act.

With the passage of time, enforcement responsibilities were changed. The FDIA
became the Food
and Drug Administration (FDA) in 1931 and was transferred
from the Department of Agriculture to what is now the Department of Health and Human
Services. The Drug Enforcement Administration for
controlled substances was established within the Justice Department.

At the beginning of the twenty-first century, drugs were available to alter
personality, to cure some types of cancer, to influence the reproductive system,
and to control the body’s response to foreign materials such as transplanted
organs. Many of these drugs were designed using powerful computers. Drugs were
even being developed to alter cellular genetics.

Bibliography

American
Pharmaceutical Association. Handbook of Nonprescription
Drugs. 18th ed. Washington, DC: Author, 2014. Print.

Brunton, Laurence L.,
et al., eds. Goodman and Gilman’s The Pharmacological Basis of
Therapeutics. 12th ed. New York: McGraw-Hill, 2011.
Print.

Griffith, H. Winter.
Complete Guide to Prescription and Nonprescription
Drugs. Rev. ed. New York: Penguin Group, 2013. Print.

Liska, Ken.
Drugs and the Human Body, with Implications for Society.
8th ed. Upper Saddle River: Pearson/Prentice Hall, 2009. Print.

Parrish, Richard.
Defining Drugs: How Government Became the Arbiter of
Pharmaceutical Fact. Somerset: Transaction, 2003.
Print.

PDR for
Nonprescription Drugs, Dietary Supplements, and Herbs. 33rd ed.
Montvale: PDR Network, 2012. Print.

Discuss the contributions and relevance of the Sophists and Socrates to the development of political theory.

Socrates and the Sophists, a group of teachers and philosophers of law and rhetoric, were contemporaries, and both made relevant contributions to political theory. Ancient Greece is where western political theory originated. The city-state of Athens was the key location for political theory's development and both Socrates and many of the Sophists resided there. Athens is also where the first primitive form of democracy was used to legislate and govern (primitive to our modern sensibility because Athenians owned slaves, while women and the poor were not allowed to participate in the government). Against this background Socrates and the Sophists discussed and debated what form of government was the most just, and, in typical philosophical fashion, they each professed contradictory notions of the ideal State.

The Sophists were interested in practical problems, like how to effectively argue and win a debate. They thought that every argument had two equally valid sides and often boasted that they could make the worse idea seem the better idea, just through their rhetorical methods. This doesn't prove the value or truth of an idea, but rather the skill of the person making the argument. The Sophists were mocked by Socrates and others as people who argued for the sake of argument or merely to impress others. Thus, even today, to call someone a Sophist insinuates that they don't argue to seek the truth but only to win the argument.

The Sophist Thrasymachus believed that most forms of government were fraudulent and only enact laws that benefit themselves, whether democratic or authoritarian. It is these artificial laws that create society and not a cooperative instinct between people. Sophists regard society, morality, and government to be artificial creations and believe that these can seem good to some and bad to others (like those Athenian slaves and women regarding the 'democracy' of their city-state). They consider all questions of morality and justice to be relative; they appear differently to each individual.

Socrates (and his student Plato, who recorded all of what we know of Socrates's philosophy) believed exactly the opposite: that society and the State were inevitable, natural, and caused no harm; that morals, such as good and evil, were absolute categories that applied to all humans and could be considered true for everyone regardless of their position in society. Socrates felt that all people have a 'natural' role in society—some are meant to be rulers and some are meant to be ruled—and if everyone knew and performed their roles society would function perfectly. But this is an inherently authoritarian system that promotes special hierarchical classes of people to leadership roles. Socrates and Plato distrusted democracy and feared that it could easily degenerate into chaos or rule by the unqualified.

Protagoras, the most influential of the Sophists, famously stated that "Man is the measure of all things." Yet Socrates would argue that the measure of all things are kinds of ideal forms that we are born with and can only know through knowledge and learning. The implication of Protagoras's idea of man is that all belief is subjective and relative to each individual person, meaning there can't exist absolute, ideal forms of anything. Thus, many Sophists believed that the lowliest citizen had just as much right to participate in his or her own governance as the wealthy elite.

In the first chapter of Lord of the Flies, what examples in the text show why the boys were on the plane?

The boys are on the island because they have been evacuated by plane from England, which is experiencing a nuclear war. Although this is never stated explicitly, there are many clues. First, the plane was full of young boys without their parents, and many of the boys don't know each other. The first thing Piggy asks is, "Where's the man with the megaphone?" indicating that a man the boys didn't know was in charge of getting them on the plane. Piggy also explains that their plane was attacked, resulting in the crash landing and the "scar" on the island that the cabin made as it traveled through the jungle. Ralph believes his father will rescue them, but Piggy points out that he overheard the pilot of the plane say that an atom bomb struck the vicinity of the airport after they escaped. "They're all dead," he informs Ralph. When Ralph finds the conch and Piggy instructs him how to blow it, they use it to call the surviving boys. Piggy then moves through the crowd of assembled boys asking names, and the boys "gave him the same simple obedience that they had given to the men with the megaphones." This suggests they had recently been in a large staging area for evacuees where men had done the same thing Piggy is now doing.

What is the setting of James Joyce's "Araby"?

First, it helps to be aware that the short story, "Araby," comes from a book of short works written by James Joyce, and this book is called Dubliners. Therefore, it makes sense to assume the stories it contains are all about various folk who live in Dublin, Ireland, the city in which Joyce himself was born and raised. Additionally, the first line of the story refers to the narrator's childhood home's location on North Richmond Street, a road located in Dublin. 

It is likely that the main events of the story took place in the early years of the twentieth century, given the descriptions of homes, schools, and daily life, though the speaker narrates these events from some time in the future, when he is an adult, using a first person objective point of view. 

What is ironic about John's proclamation that he is going to a "brave new world" in Brave New World?

The statement is ironic because the phrase "brave new world" comes from Shakespeare, but the society John is talking about has banned Shakespeare.

John has read Shakespeare, unlike the rest of the society. They feel that books other than nonfiction are not valuable.  That includes Shakespeare. We are told that “all books published before A.F. 15O” have been suppressed. This is part of the “campaign against the Past” (Ch. 3). However, since John is a savage, he has lived a completely different life. Popé brought him The Complete Works of William Shakespeare, which had been found in one of the chests of Antelope Kiva.

John’s mother tells him the book is uncivilized, but that he can practice reading on it. John does not have the best life, and he is drawn to the beauty of Shakespeare. The book helps John get in touch with his emotions.

Since he begins to experience and understand the world through the lens of Shakespeare, it kind of makes sense that John’s reaction to Lenina is an allusion to Miranda’s reaction to Alonso and Antonio in The Tempest.

The flush suddenly deepened; he was thinking of Lenina, of an angel in bottle-green viscose, lustrous with youth and skin food, plump, benevolently smiling. His voice faltered. "O brave new world," he began, then suddenly interrupted himself; the blood had left his cheeks; he was as pale as paper. (Ch. 8)

John can’t wait to see the world Lenina came from. Bernard is not impressed. He asks him to see the rest of the world before he makes a judgement. This is because Bernard knows that the world they are going back to is not a fantasy.

There are a couple of reasons that John’s reaction is ironic. Irony refers to a statement that is contradictory. There is dramatic irony with this statement, because John has no idea what this new world is like. Dramatic irony is when the reader knows something a character does not. He judges the new world by Lenina. She is beautiful, so the world she came from should be beautiful. It must be full of beautiful people. The fact that he quotes Shakespeare to praise a world that has banned Shakespeare is ironic.

The statement is also ironic because it is an expression of John’s situation. Like Miranda, he has been isolated from the rest of the world. Miranda was trapped on an island, and John was trapped in the reservation. In each case, the character is going to be leaving their isolation. Miranda might have hated the world she came to. We don't know, because the play ends. Alonso and Antonio did betray her father. John is not going to like the world he is going into either.

What are four classes of people in To Kill A Mockingbird?

After the arrival of Aunt Alexandra, Scout realizes that there is a caste system in Maycomb: Fine folks, the lower working-class people like the Cunninghams, the white-trash like the Ewells, and the Negroes.

In the Deep South in the 1930's, where there was virtually no industry, so the middle-class did not really develop until many decades later.  There were those of the upper-class who were descended from the property-owners. Then, there were those who were descended from the poorer whites, who used to be the overseers on the plantations, or they were indentured servants. Many of these became sharecroppers after the Civil War; thus, they were lower class. Men like Mr. Cunningham fell into this class. Finally, among white people there were the shiftless and lazy; men like Bob Ewell. Then, there is the underclass of the African-Americans.

It is after Jem talks with his father about the outcome of the Tom Robinson trial and learns that it was Mr. Cunningham who held out on voting against Tom, that he has his insight into the four divisions of people in Maycomb county:

"You know something, Scout? ....There's four kinds of folks in the world. There's the ordinary kind like us and the neighbors, there's the kind like the Cunninghams out in the woods, the kind like the Ewells down at the dump, and the Negroes."  

Did the novel One Day in the Life of Ivan Denisovich play a role in the growth of dissidents and/or in the independence movements in the Eastern...

Solzhenitsyn's One Day in the Life of Ivan Denisovich played an important role in the growth of dissidents, or people who disagreed with Soviet policies, and in the independence movements in the Eastern Bloc nations controlled by the Soviet Union. The book was published in 1962, when the Soviet Premier, Nikita Khrushchev, allowed a brief thaw in hard-line Soviet ideology in the press. Part of the reason Khrushchev allowed the book to be published was that it criticized the forced labor camps created by Stalin, his predecessor, and he was trying to discredit Stalin. However, Khrushchev fell out of power in 1964, and he was replaced by hardliners who again controlled the press in the Soviet Union and Eastern Bloc.

As a result, dissidents, including activists for independence movements in Eastern Bloc countries, created an underground press, publishing what was called samizdat (which means "I self-publish"). This press became a critical way for dissidents across national lines to share thoughts and press for freedom, and Ivan Denisovich and Solzhenitsyn's other work, The Gulag Archipelago, became part of the samizdat press. This underground press became a way to voice disagreement with the official Soviet line, and Solzhenitsyn became a voice of protest, particularly after he was exiled from the Soviet Union in 1974.

Why does Zinn call World War II a "people's war"?

While American historian Howard Zinn acknowledges that World War II was a "people's war" during the time it was fought, he raises questions regarding if it should continue to be thought of similarly decades later. 

Certainly there is ample evidence that points to why it would be considered a people's war. Democrats, Republicans, middle class, rich and poor were all united in the call to fight against fascism. Likewise, more than 18 million Americans served in the military at this time and more than 25 million workers supported war bonds.

However, Zinn argues that perhaps this support from the people could still be considered manufactured support, considering that many major entities in the United States—including the government, the press, and the church were all supportive of the country's involvement in World War II. 

Zinn doesn't provide a definitive answer regarding if World War II was, indeed, a people's war, but does raise many questions that call for further reflection.

What is chronic bronchitis?

Causes

With chronic bronchitis, the airways in the lungs experience inflammation. When these airways become irritated, thick mucus forms inside the airways, making it difficult to breathe.

The most common causes of chronic bronchitis include cigarette smoking and exposure to secondhand cigarette smoke. Air pollution, infections, and allergens worsen the symptoms of bronchitis.

Risk Factors

Cigarette smoking is the single greatest risk factor for developing chronic bronchitis. More than 90 percent of chronic bronchitis patients are or have been smokers, and about 15 percent of all smokers develop the disease. The more a person smokes and the longer he or she smokes, the greater the risk is of developing chronic bronchitis. Frequent and long-term smoking also increases the risk that the chronic bronchitis will be severe.

Other factors that may increase the chance of developing chronic bronchitis include long-term exposure to chemicals, dust, and other substances that have been inhaled; long-term cigar or marijuana smoking; uncontrolled asthma; and long-term exposure to air pollution.

Symptoms

Symptoms of chronic bronchitis include coughing up mucus, coughing up mucus streaked with blood, and shortness of breath (difficulty breathing). Difficulty breathing may especially occur after mild activity or exercise. Other symptoms include recurring respiratory infections that cause symptoms to worsen; wheezing when breathing; fatigue; swelling of the ankles, feet, and legs; and headaches.

Screening and Diagnosis

To diagnose chronic bronchitis, symptoms of productive cough must have been present for three or more months in at least two consecutive years, and not have been caused by another condition. A doctor will ask about symptoms and medical history and perform a physical examination.

Tests may include breathing tests to check lung function, arterial blood gas tests, chest X-ray (a test that uses radiation to take a picture of structures inside the chest), blood tests to determine complete blood count and oxygen saturation of the blood, exercise stress testing to test lung function, and a CT scan of the chest (a type of X-ray that captures 3-D images of the internal organs).

Treatment and Therapy

There is no cure for chronic bronchitis, but there are treatments that can reduce symptoms and improve lung function. The best way to reduce symptoms is to stop smoking. Short-acting bronchodilator medications may be prescribed to help open the airways in the lungs and improve breathing. Long-acting bronchodilator medication may be prescribed as well, and steroids may be prescribed to help improve breathing. Antibiotics are rarely prescribed to treat bronchitis. However, they may be needed to treat a lung infection that often accompanies the illness. A small percentage of patients may need chronic antibiotic therapy.

Oxygen therapy can restore oxygen to parts of the body depleted because of chronic bronchitis. Exercise can also help. Breathing exercises can help to improve lung function, and are usually done under the supervision of a respiratory therapist. A regular exercise program can reduce symptoms and improve lung function.

Prevention

The best way to prevent chronic bronchitis is to stop smoking, or avoiding smoking altogether for nonsmokers. Inhalation of other triggers such as air pollution, chemicals, and dust should also be avoided as much as possible. Early diagnosis and treatment of the condition will preserve lung function and reduce symptoms.

Bibliography

"Chronic Bronchitis." MedlinePlus. US National Library of Medicine, 12 Aug. 2015. Web. 28 Oct. 2015.

"Chronic Obstructive Pulmonary Disease (COPD) Includes: Chronic Bronchitis and Emphysema." CDC. US Dept. of Health and Human Services, 29 Apr. 2015. Web. 28 Oct. 2015.

Halbert, R. J., et al. “Global Burden of COPD: Systematic Review and Meta-Analysis.” European Respiratory Journal 28.3 (2006): 523–532. Print.

Lopez, A.D., et al. “Chronic Obstructive Pulmonary Disease: Current Burden and Future Projections.” European Respiratory Journal 27.2 (2006): 397–412. Print.

Mayo Clinic Staff. “Bronchitis.” Mayo Clinic. Mayo Foundation for Medical Education and Research. 1 Apr. 2014. Web. 28 Oct. 2015.

What is the theme of "The Cask of Amontillado," and why?

The theme of "The Cask of Amontillado" is the execution of a perfect crime. The whole story is taken up with Montresor's description of how he did it, not why he did it. It might be called a "howdunit" rather than a "whodunit." Poe makes this clear at the outset because he glosses over Montresor's motive with a single sentence:

THE THOUSAND INJURIES of Fortunato I had borne as I best could, but when he ventured upon insult I vowed revenge.

That is all in the past. The story is concerned only with the present. This makes it easy to visualize, almost as if it were a motion picture. The other important sentence in the opening is:

At length I would be avenged; this was a point definitely settled—but the very definitiveness with which it was resolved precluded the idea of risk.

The motive and the decision to be avenged are both "settled." What remains is to carry out the murder. This is a very adroit way of handling the story. Poe only needs to focus on one problem, which is the logistical one of luring Fortunato to his palazzo and down into his catacombs. The reader is not distracted by other considerations. The story has immediacy. Something could go wrong. Fortunato could start asking questions or balking at being led so far. Montresor has enough problems in the immediate present without needing to deal with whatever must have happened in the past.

The story ends almost as soon as Montresor finishes building his stone wall. Fifty years have passed since he completed it, but he does not say anything about what he has been doing for an entire half-century. Poe whisks the story to a conclusion with just a few words:

Against the new masonry I re-erected the old rampart of bones. For the half of a century no mortal has disturbed them. In pace requiescat!

So the past is disposed of quickly and the future—what happened after he finished building the wall—is disposed of equally quickly. Poe focuses on the little time period between the men's encounter on the street and the completion of the "immolation." Virtually everything takes place in the "present," and virtually everything can be told in description and dialogue, as in a play or movie.

The theme, of course, is revenge, but the story is concerned only with the execution of that revenge. Poe hardly even touches on Montresor's feelings about Fortunato and says virtually nothing about their relationship. This is strongly suggestive of what Ernest Hemingway was to say about his "iceberg principle" many years later.

If a writer of prose knows enough of what he is writing about he may omit things that he knows and the reader, if the writer is writing truly enough, will have a feeling of those things as strongly as though the writer had stated them. The dignity of movement of an ice-berg is due to only one-eighth of it being above water. A writer who omits things because he does not know them only makes hollow places in his writing.

—Ernest Hemingway, Death in the Afternoon

In some country the average annual growth rate of GDP was 5% in each of the first 42 years, and in each of the next 35 years was 6%. By how much...

Hello!

If a constant annual growth rate `p%` of GDP is known, the rule of 70 gives an approximation of how many years n it will take to double GDP. Specifically,

`n approx 70/p.`

As you understand, actually `(1+p/100)^n=2,` take the natural logarithm of both sides and obtain  `n ln(1+p/100)=ln2,` or `n=(ln2)/ln(1+p/100).`  For small `p` 's it is approximately `(ln2)/((p/100))=(100 ln2)/p approx 70/p.`

In our problem, `p_1=5%,` so GDP will double after about `70/5=14` years. It will double `42/14=3` times, i.e. will be multiplied by `2*2*2=8.`

After that, `p_2=6%` and GDP will double after about `70/6=35/3` years. Thus GDP will double `35/((35/3))=3` times and will be also multiplied by `8.`
The combined growth will be `8*8 = 64` times (using the 70 rule). Actually it will be `(1+5/100)^42*(1+6/100)^35 approx 60` times.

Growth by 64 times is the same as growth by `(64-1)*100%` = 6300%. This is the answer.

What is the subject of poem "The Chimney Sweeper"?

This poem is a harsh and justifiable critique of child labor. During Blake's lifetime, children were often used to climb through the flues in order to sweep the chimneys out. Boys as young as four years old were trained to do this. This was, of course, very dangerous. Children could be injured and even killed as a result of burns, cancer, and suffocation. 

In the poem's first stanza, the child is so young he can not yet say "sweep." He can only say "weep" which is tragically fitting since it resembles crying. The sound is also evocative of a baby bird crying for food or for its mother. This underscores how vulnerable these children are. 

The speaker of the poem tells us about one such child, Tom Dacre. Some child sweeps would also get stuck in the chimneys. Those that come out would be soot-stained and could have inflamed eyes. Tom has a nightmare about other sweeps stuck in black coffins. The experience of being stuck in the chimney is compared to that of being in a coffin. 

Then Tom dreams of an angel coming to rescue them all. He imagines them being free on a green plain. This symbolizes a freedom in life, to run and play as children should. Then he pictures them rising upon clouds, perhaps a reference to the heavenly afterlife. A more morbid interpretation of these dreams is that the only escape for the child worker is through death and dreams. 

Why did President Kennedy take action against Soviet bases in Cuba in 1962?

President John F. Kennedy took action against Soviet bases in Cuba in 1962 because the Soviets had secretly placed nuclear missiles on that island.  Kennedy felt that the US could not tolerate the presence of these missiles and so he felt that he had to take action when he found out about them.  This episode is known as the Cuban Missile Crisis.

In 1962, the United States was able to hit the most important parts of the Soviet Union with nuclear missiles while the Soviets were not able to hit any part of the US except for Alaska.  This was because the US had allies in Europe, not far from Russia, where they could site nuclear weapons while the Soviets had not had any such allies near to the lower 48 states of the US until Cuba became communist in 1959.  Therefore, the Soviets felt that they were at a great disadvantage.  They tried to make up for this in 1962 by placing missiles in Cuba.

When Kennedy found out about the missiles (from pictures taken by spy planes flying over Cuba), he felt that the US could not allow them.  He felt that nuclear weapons in Cuba that could hit the US constituted a grave danger to the US, one that he could not accept.  (In other words, he and his advisors felt it was acceptable for the US to be able to attack the Soviets, but not for the Soviets to be able to attack the US.)  Because of this, he ordered a naval blockade of ships coming to Cuba so they could be inspected to be sure they were not carrying more missiles or other things needed for the missile bases. This was a dangerous move, but luckily the Soviets were willing to back down and remove the missiles in exchange for a public promise by the US not to invade Cuba and a secret agreement that the US would remove its own nuclear weapons from Turkey.  This was the only action that Kennedy actually took against the bases.  He did not attack them directly or anything like that as he did not want to start a war.  The Cuban Missile Crisis is seen as one of the most dangerous incidents in the Cold War since it could have led to a war between the US and the USSR.

What evidence is there to prove that Friar Lawrence is guilty in Romeo and Juliet?

The clearest piece of evidence to indicate that Friar Laurence is guilty in Shakespeare's Romeo and Juliet is the Friar's own confession in Act 5, scene 3. In his monologue, he confesses that he married the two secretly. He further confesses to giving Juliet the sleeping potion, and says that if he did not, she would have killed herself right there. He confesses to giving a letter to Friar John explaining the plan to Romeo, and that Friar John returned the letter to him undelivered, so that Romeo never knew the contents of the message.

Had he not confessed, the deaths of Romeo and Juliet may have remained a mystery, as Friar Laurence fled from the catacombs before the arrival of the watchmen. Balthasar is found in the churchyard, and might have been implicated if it weren't for the Friar's subsequent confession.

The nurse would have known that the Friar married Romeo and Juliet, but she doesn't know of the plot that the Friar concocts to give Juliet the sleeping potion and alert Romeo, who is banished, so they can sneak away together. Juliet stops confiding in the nurse when the nurse suggests Juliet would be better off marrying Paris.

Without the Friar's confession, there wouldn't be any evidence to prove his guilt. The only witnesses are dead. The letter he penned to Romeo was returned to him by Friar John. If he hadn't had an attack of conscience, he would certainly have gone to his grave without anyone knowing the depth of his involvement.  

What is the main climax?

Since the central conflict of the story is Isabel and Ruth working against the society they live in (which sanctions their enslavement) and fighting against the various specific people who keep them enslaved, the climax is when this conflict is at its tipping point. That is, the moment where Isabel could break free and escape her mistress or where she could be caught and punished for the attempts. Typically, the climax of a story is also the most exciting part of the story as well. 

In Chains, this occurs when Isabel decides to stop waiting for the people who have said they will help her to follow through and to find freedom for herself. She steals a pass for Lockton in order to prove she is a freed slave and also decides to break Curzon out of prison to accompany her on her bid for freedom, by pretending he has died inside. This action happens in Chapters 43 and 44 of the novel, on Saturday, January 18, 1777. 

You might also include Isabel's fight with Madam, which occurs right before her escape, as a part of the climax. Since it is a moment of great conflict and excitement, I would include it as well. 

How does Harper Lee present Atticus and Scout's attitude toward him in the passage in which Scout says, "Atticus was feeble," in Chapter 10 of To...

Author Harper Lee creates irony when, in Chapter 10 of To Kill a Mockingbird, she has Scout describe Atticus as feeble. In Scout's mind, Atticus is feeble because he is older than other fathers of children her and Jem's age and does not do anything interesting. Scout's opinion that Atticus is feeble is ironic because he is actually the exact opposite. In reality, Atticus has extraordinary strength of character and a very unusual ability to act bravely, as Scout soon discovers.

Scout sees Atticus as feeble because, due to what she thinks of as his old age, which is only 50, he is unable to do many things such as play tackle football with Jem. She also sees his physique as portraying his feebleness, such as the fact that he wears glasses and is "nearly blind in his left eye." Finally, his job contributes to her view that he is feeble. In Scout's mind, Atticus does not have an interesting job like other fathers; for example, he does not drive a garbage truck, farm, work as a sheriff, nor work in a garage as a mechanic. Instead, all he does is work in an office, which could not "possibly arouse the admiration of anyone" (Ch. 10).

Little does Scout realize that we learned a great deal about Atticus's bravery earlier in Chapter 9. Atticus is brave enough to face the wrath of society by deciding to put his all into defending Tom Robinson, despite the rest of society's racist views that Robinson must be guilty simply because he is African American. In Chapter 10, we further witness Atticus's bravery when he acknowledges the reality that only his sharpshooting skills can save the neighborhood from a rabid dog and submits to taking on the task, even though he hates the idea of killing any living thing. Hence, Scout's opinion at the start of Chapter 10 is ironic and extremely incorrect, as she soon realizes.

In The Cay, if Phillip's mother were aware of Timothy's sacrifice on her son's behalf, do you think her views about black people would change?

This is an interesting question. When the story begins, we are told that Phillip’s mother is upset that the family is living in Curaçao and misses her life in Virginia where the Enrights had had a small house, experienced the changing seasons, and had many friends. Phillip notes that she was

“Homesick for Virginia, where no one talked Dutch, and there was no smell of gas or oil, and there weren’t as many black people around.”

This is the first hint of Grace’s racism. However, later he adds that she is very over-protective. She always worries about Phillip. She worries about ordinary things (Phillip falling out of a tree), and rare occurrences (he might cut himself with a pocket knife). She especially warns him to stay away from the black workers on the schooners in St. Anna Bay. Phillip finds his interaction with the black workers fun, but his mother says, “They are different and they live differently. That’s the way it must be.”

As Phillip begins his relationship with Timothy, he reflects on his mother’s feelings and, in his despair in the aftermath of the shipwreck, starts to agree with her.

As their relationship evolves, Phillip grows to respect Timothy. His blindness allows him to “see” the truth that there is no difference between them that is the result of their color. Eventually, Phillip loses all traces of his inherited racism. When he returns to Curaçao, he prefers the company of black people who remind him of Timothy.

We can surmise that his mother would probably have changed her view on black people if she had known about Timothy’s efforts to rescue, support and protect her son, based on the end of the book, where Phillip’s disappearance has changed Grace so profoundly that she no longer wants to leave the islands.

Based on this change, it would seem that Grace would have the ability to lose her racism in the same way that her son does, through experience with black people. If she were aware of Timothy's sacrifice, it would change her perspective.

What is periodontitis?

Causes and Symptoms

Periodontitis,
is the advanced stage of gum disease (or periodontal disease) that occurs when the earlier stage of gum disease, gingivitis, is left untreated or if treatment is delayed. Gingivitis is caused by bacteria in plaque and tartar, which if left on the teeth for too long can inflame and infect the gums. In periodontitis, the infection and inflammation spread from the gums (gingiva) to the ligaments and bones that support the teeth. Dental plaque begins to spread down the roots of the teeth, and the gums become infected, which causes damage to the bone and fibers (periodontal ligament) that support the teeth. As the disease progresses, the gums pull away from the teeth, allowing more food and plaque to be trapped under them and inviting more damage to occur. In advanced stages of the disease, the teeth become increasingly loose, and shifting may occur because of widespread damage to the bone and ligaments holding the teeth in place. The bite may therefore shift, and there may be difficulty chewing. Loss of support causes the teeth to become increasingly loose and eventually fall out.

Periodontal disease can be caused by the use of smokeless tobacco.
In the areas where the tobacco is held against the cheek, the tobacco and by-products cause irritation and infection of the gums. The gums begin to recede, and periodontal disease affects the teeth in the area. The area is also highly prone to oral cancer.

The early symptoms of periodontitis tend to resemble those of gingivitis, with mouth sores and swollen gums that are tender when touched but otherwise painless. Progressive symptoms include swollen gums that are bright red or reddish-purple. The gums may appear shiny and may bleed easily, and there may be odor to the breath.

Treatment and Therapy

Treatment methods for advanced (chronic) periodontal disease include aggressive oral hygiene instruction and reinforcement and evaluation of the patient’s plaque control. Scaling and root planing to remove microbial plaque and calculus below the gum line, followed by surgery to reduce the depth of the periodontal pocket, is the most common office-based procedure to help manage the disease. Lesions may be treated with adjunctive antimicrobial therapy and antibiotics. Long-term maintenance is necessary. Flossing, more frequent brushing, and mouthwashes are recommended to the patient between regular dental visits.

The long-term outcome of treatment may depend upon patient compliance and professional maintenance at appropriate intervals. If the primary teeth are affected, then the infection should be monitored closely in order to avoid possible attachment loss. The goals of periodontal therapy include altering or eliminating the causative microbes and contributing risk factors for periodontitis, thereby arresting advancement of the disease and preserving the teeth. Ultimately, it is desirable to prevent the recurrence of periodontitis. Because of the complexity of aggressive periodontal disease with regard to systemic factors, immune defects, and microbial flora, however, control may not be possible in all instances. In such cases, a reasonable treatment objective is to slow the progression of the disease.

Perspective and Prospects

Periodontitis is the primary cause of tooth loss in adults. This disorder is uncommon in childhood, but the incidence rate increases during adolescence. In addition to a lack of good oral hygiene, certain risk factors have been associated with periodontitis. It is more severe and occurs with a frequency two to five times greater among patients with diabetes mellitus. Smoking can increase the risk of developing severe periodontitis by a factor of three to six times, depending on smoking duration and number of cigarettes.

While periodontitis can be managed effectively with current surgical and nonsurgical therapies in some patients, other patients are less responsive to the treatment options available. Most people with periodontitis receive little or no treatment at all.

Bibliography:

Detienville, Roger. Clinical Success in Management of Advanced Periodontitis. Translated by Nicolai Johnson. Chicago: Quintessence International, 2005.

Edwardsson, S., et al. “The Microbiota of Periodontal Pockets with Different Depths in the Therapy-Resistant Periodontitis.” Journal of Clinical Periodontology 26, no. 3 (1999): 143–152.

"Gum Disease." MedlinePlus, Apr. 25, 2013.

"Gum Disease Information." American Academy of Periodontology, 2013.

Healthnet: Connecticut Consumer Health Information Network. "Your Dental Health: A Guide for Patients and Families." UConn Health Center, Nov. 27, 2012.

Lamont, R. J., and H. F. Jenkinson. “Life Below the Gum Line: Pathogenic Mechanism of Porphyromonas Gingivalis.” Microbiology and Molecular Biology Reviews 62, no. 4 (1998): 1244–1263.

Page, R. C. “The Role of Inflammatory Mediators in the Pathogenesis of Periodontal Disease.” Journal of Periodontal Research 26 (1991): 230–242.

Page, R. C., and K. S. Kornman. “The Pathogenesis of Human Periodontitis: An Introduction.” Periodontology 2000 14 (1997): 9–11.

"Periodontal (Gum) Disease: Causes, Symptoms, and Treatments." National Institute of Dental and Craniofacial Research, Aug. 2012.

Reynolds, J. J., and M. C. Meikle. “Mechanism of Connective Tissue Destruction in Periodontitis.” Periodontology 2000 14 (1997): 144–157.

Rose, Louis F., et al., eds. Periodontics: Medicine, Surgery, and Implants. St. Louis, Mo.: Mosby, 2004.

In Act I of Romeo and Juliet, why is Romeo so unhappy?

Romeo is unhappy because the girl he is in love with doesn't return that affection. After the street fight in Act I, Scene 1, Lord Montague, Romeo's father, comments that his son seems sad and depressed. He asks Benvolio to discover Romeo's problem. Romeo tells Benvolio that his days are long because he is "Out of her favor where I am in love." He is seemingly confused and frustrated by this unrequited love and launches into a series of oxymorons describing his plight: "O brawling love, O loving hate." He further explains that the girl he loves basically refuses to love and has chosen to live "chaste." He compares her to the Greek goddess Diana, who was the patroness of virginity. She refuses to be talked to about love or take gifts. She is very beautiful but won't share her beauty. Romeo says,

Well in that hit you miss. She’ll not be hit
With Cupid’s arrow. She hath Dian’s wit,
And, in strong proof of chastity well armed,
From love’s weak childish bow she lives uncharmed.
She will not stay the siege of loving terms,
Nor bide th’ encounter of assailing eyes,
Nor ope her lap to saint-seducing gold.
O, she is rich in beauty, only poor
That, when she dies, with beauty dies her store.

The audience doesn't learn who the girl is until Romeo reads the list of those invited to Capulet's party in Scene 2 and sees Rosaline's name. Benvolio urges Romeo to go to the party and compare Rosaline to the other women of Verona. Benvolio is sure Romeo will see someone more beautiful. Of course, Benvolio is correct as Romeo meets Juliet at the party.

What is phenylketonuria (PKU)?

Causes and Symptoms

Phenylketonuria (PKU) is a genetic disorder, occurring in about one in 10,000 births, that disrupts the metabolism of the amino acid phenylalanine. The disorder is caused by a deficiency of phenylalanine hydroxylase, a liver enzyme that catalyzes the conversion of phenylalanine to tyrosine. Since normal phenylalanine metabolism is blocked, the amino acid accumulates in blood and tissues, resulting in progressive, irreversible mental retardation and neurological abnormalities. Most forms of PKU are caused by a mutation—more than two hundred mutations are now characterized—in the gene for phenylalanine hydroxylase. A small percentage of infants with PKU have a variant form of the condition, known as malignant PKU. This disorder is caused by a defect in the synthesis or metabolism of tetrahydrobiopterin, a cofactor for the conversion of phenylalanine to tyrosine, or in other enzymes along the pathway. Without treatment, malignant PKU causes a progressive, lethal deterioration of the central nervous system.

Infants with classic and malignant PKU appear normal; however, if untreated, the condition severely impairs normal brain development and growth after a few months of age, causing mental retardation, seizures, eczema, and neurological and behavioral problems. Affected infants have plasma phenylalanine levels ten to sixty times above normal, along with normal or reduced tyrosine levels and high concentrations of the metabolite phenylpyruvic acid in their urine.

Newborns are screened routinely for PKU within the first three weeks of life, usually by using whole blood obtained from a heel prick. Elevated phenylpyruvic acid levels also can be detected in urine of infants with PKU after adding a few drops of 10 percent ferric chloride, resulting in a deep green color. Newborns often have transient PKU—elevated phenylalanine and phenylpyruvic acid levels in the first few weeks of life that normalizes—so classic PKU should be distinguished from transient conditions. Elevated phenylalanine levels that persist beyond a few weeks of life, accompanied by normal or low tyrosine levels, usually indicate an inborn error of metabolism. Malignant PKU is usually diagnosed by detecting biopterin metabolites in urine or showing that tetrahydrobiopterin supplementation restores normal phenylalanine and tyrosine levels.

Babies of mothers with PKU are at high risk of brain damage, impaired growth, and malformations of the heart and other organs. Managing maternal phenylalanine levels at near normal concentrations appears to be crucial to preventing these cognitive and neurological defects.

The clinical basis for the damaging effects of PKU on the brain is unclear. Elevated phenylalanine levels may interfere with brain myelination or neuronal migration during development. In addition, PKU decreases the levels of the neurotransmitters dopamine and serotonin, which may be the basis for its neurological effects.

Treatment and Therapy

The detrimental effects of PKU can largely be controlled by maintaining phenylalanine levels in the normal range through a strict low-phenylalanine diet. This complex diet, often supplemented with tyrosine, prevents the buildup of phenylalanine and its metabolites in body tissues. Children whose phenylalanine levels are regularly monitored and managed can achieve normal intelligence and development. In infants with malignant PKU, tetrahydrobiopterin or cofactor supplements are required to control phenylalanine levels successfully.

Treatment for PKU must begin at a very early age, before the first three months of life, and usually continue through adulthood, or else some degree of mental retardation or neurological abnormalities is expected. Screening newborns for PKU before three weeks of age is mandated in all fifty US states. Strict control of phenylalanine levels also is indicated for pregnant women with PKU because their babies are at high risk for severe brain damage.

The successful treatment of PKU depends on managing phenylalanine levels. However, the diet is complex and challenging to sustain over many years. Since phenylalanine is an essential amino acid, found in virtually all proteins, maintaining adequate nutrition is nearly impossible on a low-phenylalanine diet. The treatment requires rigorous protein restriction and the substitution of most natural proteins in meat, fish, eggs, and dairy products. Phenylalanine intake must not be too restricted, however, or else phenylalanine deficiency can occur.

In some cases, dietary treatment for PKU can be discontinued or made less restrictive as children age, without causing severe effects. In many cases, however, the ill effects of the disorder carry into adulthood unless dietary management is continued over the long term. Untreated adolescents and adults may exhibit behavioral or neurological problems, difficulty concentrating, poor visual-motor coordination, and a low intelligence quotient (IQ).

Perspective and Prospects

Phenylketonuria was the first inborn error of metabolism shown to affect the brain. This genetic disorder was discovered in the 1930s by Ivar Asbjørn Følling. Since its discovery, PKU has been controlled successfully by rigorous newborn screening programs and careful dietary management of phenylalanine levels in pregnant women and in children with the disease. Newer research has focused on improving medical formulations for low-phenylalanine diets and amino acid supplementation for children and adults.

In the 1980s, clinical trials examined the use of dialysis-like procedures that allowed the rapid breakdown of phenylalanine in the blood. The treatment applies to pregnant women with PKU or those with severely elevated phenylalanine levels resulting from stress or illness. In the late twentieth century, PKU became the focus of gene therapy research. Animal models of PKU have been successfully treated by introducing normal phenylalanine hydroxylase deoxyribonucleic acid (DNA) into the liver cells of mice. Since the underlying genetic defects are known in most cases of PKU, gene therapy appears a likely research focus for long-term treatment.

Bibliography

Behrman, Richard E., Robert M. Kliegman, and Hal B. Jenson, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia: Saunders/Elsevier, 2011.

Chopra, Sanjiv. Dr. Sanjiv Chopra's Liver Book: A Comprehensive Guide to Diagnosis, Treatment, and Recovery. New York: Simon & Schuster, 2002.

Kimball, Chad T. Childhood Diseases and Disorders Sourcebook: Basic Consumer Health Information About Medical Problems Often Encountered in Pre-adolescent Children. Detroit, Mich.: Omnigraphics, 2003.

Marlow, Amy. "Phenylketonuria." Health Library, November 26, 2012.

Martin, Richard J., Avroy A. Fanaroff, and Michele C. Walsh, eds. Fanaroff and Martin’s Neonatal-Perinatal Medicine: Diseases of the Fetus and Infant. 9th ed. St. Louis, Mo.: Mosby/Elsevier, 2011.

MedlinePlus. "Phenylketonuria." MedlinePlus, May 13, 2013.

Moore, Keith L., and T. V. N. Persaud. The Developing Human. 9th ed. Philadelphia: Saunders/Elsevier, 2013.

National PKU News. National PKU News, March 2013.

Parker, James N., and Philip M. Parker, eds. The Official Parent’s Sourcebook on Phenylketonuria. San Diego, Calif.: Icon Health, 2002.