Which two planets have the most moons?

Moons are the natural satellites of a planet and these celestial bodies orbit around the planet. The name of Earth's natural satellite is Moon. Similarly, many of the other planets of our solar system also have moon/s. Here is a list of number of moons of each planet in our solar system:

Mercury: 0 moons

Venus: 0 moons 

Earth: 1 moon

Mars: 2 moons

Jupiter: 67 moons* (including 17 provisional moons)

Saturn: 62 moons* (including 9 provisional moons)

Uranus: 27 moons 

Neptune: 14 moons* (including 1 provisional moon)

Thus, Jupiter and Saturn have the largest number of moons, as compared to other planets of our solar system. 

The 4 most famous moons of Jupiter are known as Io, Ganymede, Callisto and Europa. The most famous moon of Saturn is known as Titan. 

Note that the number of moons of each planet may change (in future) depending upon the observation of newer celestial bodies with better technology in the future. 

Hope this helps.

How is Nerissa a loyal friend to Portia in Shakespeare's The Merchant of Venice?

Portia is a wealthy heiress whose father has died and left her with no other family. Nerissa is Portia's servant, and of a lower social class, but she seems to act more as a sister and friend. Nerissa is Portia's listening ear and empathetic voice. Not only does she bounce Portia's thoughts off of her wisdom, but she also accompanies Portia on all her mental, emotional, and physical adventures. When the audience first sees Nerissa, she is helping Portia categorize all of her suitors to analyze their good qualities, if any. She is also the one who reminds Portia of Bassanio, the one, in her mind, most suited for marrying her mistress.

Nerissa also goes undercover with Portia as a law clerk to assist with Shylock's proceedings against Antonio. Nerissa could have declared Portia a fraud, but she is a loyal friend for life. The two women are so connected, they also play a joke on their husbands together by retaining their wedding rings while in disguise. When the men come home afterwards, they are caught in their faults, which helps to prove the follies of men in their minds and teach the men a lesson. Nerissa and Portia are both forgiving, however, and reveal their parts in the trial and how they set their husbands up for the joke. Therefore, Nerissa is more than a servant for Portia; she is her sister and partner in crime, her loyal assistant and supporter. Anything Portia does, Nerissa also does because of her sisterly love and friendly loyalty.  

What is a word in Lois Lowry's The Giver that starts with q?

I am going to give you two answers because I am not sure if you are looking for a vocabulary word that you might not know, or if you are looking for a word of special significance to the book. 

A vocabulary word that starts with q is “quizzically.” This means to ask questioningly because something is puzzling or confusing. 

There was a question bothering Jonas. "Sir," he said, "The Chief Elder told me—she told everyone—and you told me, too, that it would be painful. So I was a little scared. But it didn't hurt at all. I really enjoyed it." He looked quizzically at the old man (Chapter 11). 

The context of this word’s use is that Jonas is asking The Giver about his training. He has only been training for a short time, and he understands the basics about the memories but not what is really happening. Jonas has been told he needs to be brave and will face physical pain, and he is wondering when and how. 

Although “quizzically” is an interesting word, it does have relevance to another important q-word in the book, “question.” No one in Jonas’s community asks questions about the way things are. When Jonas begins his training, he has many questions because sees many things he has never seen before, such as the books in The Giver’s annex. 

In his mind, Jonas had questions. A thousand. A million questions. As many questions as there were books lining the walls. But he did not ask one, not yet (Chapter 10).

Thus, the word “question,” while related to the word “quizzically,” is a word of symbolic meaning to the book.  The moral of the story is that we need to ask questions. If we just accept things as they are, we are allowing life to pass us by and possibly permitting atrocities to happen.

What is the molarity of a 250 mL H2SO4 solution that was made from 20 mL of a 10 M stock solution?

There are two ways to solve this question. 

Since the sulfuric acid solution is made from a stock solution, the number of moles of sulfuric acid remains the same. In other words, the number of moles of sulfuric acid in the 20 mL, 10 M stock solution is same as those in the 250 mL of solution. Since molarity is the ratio of moles of solute and the volume of the solvent,

number of moles in 20 mL, 10 M stock = molarity x volume.

First we need to convert 20 mL to liters (L):

20 mL x ( 1 L / 1000 mL) = .02 L

 = 10 M x .02 L moles = 0.2 moles H2SO4

These 0.2 moles of sulfuric acid are also present in the 250 mL of solution.

To solve for the concentration of the resultant solution, we must first convert 250 mL to L.

250 mL x (1 L / 1000 mL) = .25 L

concentration (M) = moles/volume = 0.2/(.25) = 0.8 M.

We can also use the equation:

C1V1 = C2V2

to solve this numerical, since this is a simple dilution scenario (stock solution is diluted by adding more solvent). Here C1 and C2 are concentrations of the solutions and V1 and V2 are their volumes.

Thus, 10 M x .02 L = C2 x .25 L

solving this, we get C2 = 0.8 M.

Therefore, option A is correct.

Hope this helps.

Was Julius Caesar an astute politician, a military genius, a scheming opportunist, a visionary or a combination of all these ?

Based on the vast amount of research done on Caesar’s life and legacy and the variety of scholarly perspectives that have emerged, it is safe to say that he was an astute politician, a military genius, a scheming opportunist, AND a visionary.

Caesar was able to gain much of his initial power because of his familial ties to the prestigious Julian clan. He climbed the political ladder from quaestor, to aedile, to praetor, to provincial governor, to consul, and eventually to ultimate dictator of Rome. His path to power was remarkably intuitive, which is indicative of an astute politician.

Scholars widely agree that Caesar was one of the greatest military geniuses of all time. Aside from his massive success during his time in Gaul, he was also successful in ending the Great Roman Civil War (49-45 BCE)—one of many conflicts that foreshadowed the end of the Republican political system. After the war, Caesar reached his peak in political power as Perpetual Dictator (Latin: Dictator perpetuo). Before this, dictatorship was only meant to be a temporary governing solution in times of crisis. But Caesar’s influence was so profound at this point that he was able to maintain that title for the rest of his life. This paved the way for the establishment of the Empire.

Needless to say, Caesar’s rise to power was fraught with controversy. Many other politicians perceived him as a scheming opportunist who disrespected the traditional political system by altering it to suit his own agenda—which ultimately led to his assassination.

Be that as it may, Caesar’s opportunism did not undermine him as a visionary. He knew Rome was in desperate need of debt relief and reform, and he took whatever measures necessary to make those improvements. He was widely loved by the Roman people, especially those from the lower and middle classes who directly benefitted from his influence. In addition, Caesar was the first Roman figure to be deified, which indicates how profound his leadership was!

What precautions are taken during blood transfusion?

Blood transfusions are an important part of emergency medical services and operative procedures, but it's not as simple as taking blood from one person and putting it into another. There are several different types of blood with certain antibodies which aren't always compatible with one another. What's more, many illnesses may be passed on through blood. To make sure that someone receiving a blood transfusion doesn't become sick from or have an allergic reaction to the blood, several things happen prior to the actual transfusion.

First, when a person donates blood, he or she must be clear of any blood-borne illnesses like Human Immunodeficiency Virus or Hepatitis. It's also helpful if someone can state their blood type when making a donation, although blood can be tested afterwards. Blood is packaged in sterile plastic bags and then clearly labeled. There are eight different types of blood based on antibody compositions — A, B, AB, and O, each of which may be either RhD positive or negative. Blood may go through additional screening for potential illness-causing agents or be separated for special-purpose transfusions of white or red blood cells, platelets, or plasma.

After any additional screening or separation, blood is sent to a hospital or doctor's office, where it remains in a refrigerated storage space to prevent cell degradation. When a patient needs a transfusion, medical staff always double check a person's blood type before administering an intravenous transfusion. Giving a patient the wrong type of blood can make them break out in a serious reaction as their body's immune system tries to fight off foreign antibodies. Some people can receive or donate any type of blood regardless of antibody composition. Type O+ blood is considered the "universal recipient" of blood products, while type O- is the "universal donor."

When it's time to give the transfusion, an intravenous catheter is inserted. The area is cleaned with an alcohol swab and a fresh, sterile needle is used to create the puncture. The catheter is then flushed with saline solution to make sure there is no tissue or blood cells blocking the portion inside of the patient's vein. Blood transfusions are typically co-administered with saline solution in a slow fashion to prevent any shock to the body. In emergency situations where someone has lost quite a lot of blood or has inadequate platelets, a transfusion might be done more quickly.

Perhaps the most important part of precautions for blood transfusions is the routine testing of blood for pathogens. This screening, performed by organizations like the Center for Disease Control, ensures a healthy and safe supply of blood is available for people who need it. 

In The Crucible, why does Abigail Williams accuse people at the end of Act 1?

Abigail has been through a lot in this first act.  First, she dealt with the suspicions of her uncle, the Reverend Parris, and his concerns about her activities in the woods as well as her reputation in the town.  Next, Mary Warren insists that they have to tell what they did in the forest, and Abigail's cousin, Betty Parris, calls her out for drinking a "charm to kill Goody Proctor" and not confessing it.  Then, her old flame, John Proctor, arrives, and she must listen while he tells her that their affair is over although she still loves him.  Then, the Reverend Hale questions her, "grasping" her arms, clearly suspicious of her and what she seems to be hiding.  Ultimately, she accuses Tituba, it seems, in order to deflect attention and suspicion from herself; she knows her word will be taken over a slave's any day, and she is desperate to escape the negative attention focused on her thus far.

However, then Hale begins to speak gently to Tituba, "tak[ing] her hand" and telling her that she is "God's instrument put in [their] hands [...] to help [them] cleanse [their] village."  He tells her that she has a special purpose, making her feel special, and so she accuses Goody Good and Goody Osburn, perhaps, to please him and to make her story seem more believable.  The room is electrified, and people instantly believe Tituba.  Abigail seems to sense an opportunity -- stage direction states that she is "staring as though inspired" -- and suddenly she, too, confesses, repeating Tituba's two accusations (for credibility) and adding one other.  She has an opportunity, here, to gain power in her household and in the town through her accusations.  In addition, when she eventually accuses Elizabeth Proctor (the thought of which is perhaps what "inspired" her), she has the chance to get John all to herself.  She can also accuse anyone in the town, and she is likely to be believed: anyone who's ever spoken out against her, anyone she simply doesn't like, and so on.  Hysteria seems to take over when Betty chimes in with her accusations, and she and Abigail name many more "witches" before the act ends. 

Can you describe Leafy Crawford from Their Eyes Were Watching God by Zora Neale Hurston?

In Their Eyes Were Watching God, Leafy Crawford is Janie's mother.  Leafy is mixed race, as Nanny was raped by the slave master in charge of her plantation.  Throughout Leafy's childhood, Nanny tried to protect her and give her a life that was better than the one Nanny had.  So Nanny runs away with Leafy from the plantation and finds a place to live in west Florida.  When Leafy becomes a teenager, Nanny has dreams that Leafy will become a school teacher; however, Leafy is raped by her own teacher and becomes pregnant with Janie.  The man is never charged because he runs away, and once Janie is born, Nanny is left in charge of raising the girl.  Leafy turns to alcohol to deal with her hardships and eventually runs off herself.  Janie knows little about her mother as a person.

What are five character traits of Thomas in Gathering Blue?

Thomas the Carver lives in the Council Edifice with Kira. Like Kira, he was orphaned and taken in by the Council of Guardians because of his artistic abilities. Thomas can be described as friendly, conscientious, previously mischievous, helpful, and complacent.

Thomas makes Kira feel at home in the Edifice, explaining to her about the tenders and how various things work there. His friendliness makes life at the Edifice happier and more comfortable for Kira.

Thomas is conscientious about the work he performs for the guardians. He works at his meticulous carving of the Singer's staff until he gets headaches and becomes fatigued.

Kira learns from Thomas that he used to be more mischievous than he is now. In those days, he carved a key that fit the locks of every room in the Council Edifice, which they are able to use to meet Jo. Thomas reveals that he used to go out at night and snoop in all the rooms; he was "just like Matt."

Thomas is helpful when Kira needs assistance. He goes with her to investigate the crying, and they locate Jo's room together. When she sees Matt preparing to go on the hunt, she asks Thomas to help her, and he brings Matt in and bathes him in his tub. Later, when Kira is worried about Matt's disappearance, Thomas accompanies her to the Fen to look for the boy.

These characteristics make Thomas a good companion for Kira. An area where the two of them don't see eye to eye, however, is in their desire to bring change to their society. When Kira suggests about the future represented by the blank spots on the robe and staff that "maybe we can make it different," Thomas is skeptical. When Kira suspects that the guardians have killed the artists' parents deliberately and are using their talents for their own purposes, Thomas shrugs it off. He is content to have a good place to live, good tools, plenty to eat, and work to do. He is complacent with his life.

Before the time frame of the story, Thomas had been a mischievous boy. Now he is conscientious, friendly, and helpful, but his complacency makes him a less intriguing character than Kira.

What is the realization that Cole has during the storm in Touching Spirit Bear?

Cole realizes that he is small and insignificant in nature, and all alone. 

Cole is a very angry young man.  He blames everyone else for his shortcomings and his mistakes.  When he agrees to Circle Justice, he does not really plan to change.  He thinks the whole thing is a joke.  

The experience of being alone on the island is a wake-up call for Cole.  He is left there to fend for himself, and he is expected to reflect.  He acts out at first.  He tries to swim away.  He burns down his cabin.  Worst of all, he attacks the Spirit Bear. 

Trying to swim away is an awakening for Cole.  He is unsuccessful, and ends up in pain on the shore.  He has failed, and he is trapped. 

Then he became aware of another feeling. Stronger than any burning in his arms and belly, more haunting than the darkness that surrounded him, was the realization that he was alone, totally alone with himself.

And it scared him. (Ch. 5)

When Cole attacks the spirit bear, he is acting out of his usual anger.  Cole thinks that the bear should be afraid of him.  He is angry that it isn’t.  When the bear casually mauls him, it is a shock to Cole.  He realizes that the universe does not answer to him.  He is actually very small and insignificant in the grand scheme of things.

Badly injured, Cole assumes he will just have to stay there until he dies.  During the storm, he ponders the meaning of his existence.  He watches some baby birds die.  The world continues, and nature rages on, and Cole is unimportant. 

Eventually, Cole is rescued.  He becomes a different person after he recovers.  It is still a long road to recovery, because Cole has far to go, but he becomes less angry and more reflective.  He really does change because of the Circle Justice lessons.

What images are conjured with Duncan's words in Act I, Scene 4 of Macbeth?

In Act I, Scene 4 of Macbeth, with King Duncan's words there are images of Nature and light that contrast with the imagery of the three witches in the previous scene.

Whereas in the previous scene the witches' nature is menacing and obsessive and dark, in Scene 4, the images of nature are depicted as nurturing and bountiful. Duncan states that things have occurred with such rapidity that he has been unable to reward Macbeth properly and quickly enough:

That swiftest wing of recompense is slow

To overtake thee. (1.4.18-19)

In the first line, King Duncan speaks with a metaphor for his gratitude--"That swiftest wing of recompense" (1.4.18)--that was unable to reach his noble soldier quickly enough. The image created by this figure of speech is that of a bird. To this, Macbeth replies that he has had his reward by having the honor to serve King Duncan.

In his next lines, Duncan creates the image of a garden as he says,

I have begun to plant thee..." and like the good farmer, he will labor
To make thee full of growing.(1.4.29-30)

This nature imagery continues with the suggestion of a bird when the king thanks Banquo, 

...let me enfold thee (as a bird covers her young beside her--takes her "under her wing")
And hold thee to my heart. (1.4.32-33)

Then Duncan advises Macbeth, Banquo, and the others that although he will make his son Malcolm his heir, he will reward the others:

But signs of nobleness, like stars, shall shine (1.4.42-43)

On all deservers. 

Here, then, is also light imagery with that of nature in the use of the word stars.

What are staphylococcal infections?

Causes and Symptoms

Under the microscope, staphylococci bacteria are observed to grow in irregular, grapelike clusters from which they derive their name. Individually, the organisms are spherical and appear purple (positive) when stained with Gram technique. Staphylococci are found predominantly living on the skin and mucous membranes of mammals and birds and usually exist in a benign symbiotic relationship with their hosts. When the barrier imposed by either the skin or mucous membranes is breached, however, staphylococci may then cause disease, assisted by a variety of enzymes and toxins that they are able to manufacture. Many strains of staphylococci, such as Staphylococcus aureus, produce coagulase, which catalyzes the formation of a clot from fibrinogen proteins in the blood. Hyaluronidases, lipases, and other proteolytic enzymes carve out a cavity within the clot, which is covered by a coagulase-generated fibrin coat, and an abscess is formed. Abscess formation is one of the hallmarks of
staphylococcal infection and can be found in virtually any organ in the body as a result of local invasion or spread to the site via the bloodstream.

Staphylococcal strains are able to produce a variety of proteins called exotoxins that have significant roles in determining the type of illness that results. Superantigens, such as toxic shock syndrome
toxin-1 (TSST-1), target the circulatory system and can markedly lower blood pressure. TSST-1 producing strains have caused disease not only by growing in vaginal tampons but also while simultaneously causing postsurgical wound infections. Food poisoning
results after ingesting food that is contaminated with staphylococcal strains that produce enterotoxins. The toxins are produced in the food after contamination from the colonized noses or infected skin of food handlers through sneezing or direct contact. The enterotoxins are relatively heat-stable and do not result in any unusual taste, odor, or appearance of the food. Abdominal cramps, nausea, vomiting, and diarrhea occur one to six hours after ingestion of the contaminated food containing the toxin. This is not a true infection, as it is the preformed toxin that produces the illness. Exfoliative toxin is produced by the
strains causing scalded skin syndrome. The illness is manifested by fever and reddened skin that subsequently peels off.

Staphylococci are able to form a variety of cytotoxins that damage the membranes of bodily tissues. These toxins are able to destroy red and white blood cells as well as organ cells. Leukocytolytic activity from staphylococci was first reported in 1932 and the Panton-Valentine leukocidin (PVL) was named in honor of these scientists. PVL is produced by strains of S. aureus causing skin and soft tissue infection and pneumonia in the community (outside the hospital).

S. aureus is the preeminent pathogen causing infection in hospitalized patients. It is the most common cause of surgical wound infections. It is joined by another species, S. epidermidis, which can produce slime enabling the bacteria to adhere to the surfaces of medical devices such as vascular catheters, central nervous system
shunts, artificial heart valves, and prosthetic joints. Together, these two species account for a large number of hospital-acquired infections.

Infection of skeletal muscle and contiguous tissues is called pyomyositis or necrotizing fasciitis. This type of infection has been common in developing countries with tropical climates, but since the 1970s it has been seen more frequently in modern countries with temperate climates. The pathogenesis of pyomyositis is not completely understood. Some cases follow trauma, and there are a number of risk factors, such as intravenous drug abuse, human immunodeficiency virus (HIV) infection, and skin diseases. Other cases occur in healthy individuals without any apparent risk factor. Recently, virulent strains of community-acquired methicillin-resistant S. aureus (MRSA) have caused pyomyositis in the United States.

S. saprophyticus is an important cause of urinary tract infections in young women. The infection may be manifested by cloudy or blood-tinged urine and dysuria. It is associated with sexual intercourse or swimming. Various adhesions and the enzyme urease contribute to its ability to produce infection of the urinary tract.

Treatment and Therapy

Specific treatment of a staphylococcal infection hinges on administering an effective antibiotic. MRSA is a type of S. aureus that is resistant to antibiotics called beta-lactams, which include methicillin and other related, commonly used antibiotics. Vancomycin, an antibiotic developed in the 1950s, has remained effective for nearly all strains, but it must be given intravenously and has some serious potential side effects. Some newer antibiotics, daptomycin and linezolid, are effective against MRSA and have been used successfully to treat infections.

Antibiotics are not the only measure necessary to cure these infections. Surgical or percutaneous catheter drainage of abscesses, surgical debridement of dead tissue, and the removal of medical devices or protheses are often necessary. Other medical supportive modalities, such as fluid replacement, vasopressors, or mechanical ventilation, may be required.

Perspective and Prospects

The Centers for Disease Control and Prevention (CDC) is collaborating with other medical organizations to develop and promote strategies to reduce the transmission of staphylococci, primarily MRSA, in both health care and community settings. The CDC has also launched a campaign to prevent antimicrobial resistance
by educating both the public and health care providers about unnecessary and inappropriate antibiotic usage. Legislative efforts have been directed at eliminating the use of antibiotics in animal feed to assist in preventing resistance.

Newer antimicrobial agents continue to be developed, but the stream has slowed. Molecular-based treatments directed toward toxins and other virulence factors are being actively pursued.

Bibliography

Crossley, Kent B., and Gordon L. Archer, eds. The Staphylococci in Human Disease. 2d ed. Hoboken, N.J.: Wiley-Blackwell, 2010.

Kasper, Dennis L., et al., eds. Harrison’s Principles of Internal Medicine. 16th ed. New York: McGraw-Hill, 2005.

Koneman, Elmer W. The Other End of the Microscope: The Bacteria Tell Their Own Story. Washington, D.C.: ASM Press, 2002.

Mayo Clinic. "Staph Infections." Mayo Clinic, June 9, 2011.

McCoy, Krisha. "Methicillin-Resistant Staph Infection." Health Library, September 30, 2012.

MedlinePlus. "Staphylococcal Infections." MedlinePlus, April 19, 2013.

In George Orwell's Animal Farm, how are the pigs able to deceive the other farm animals under the guise of "animalism"? What lies do Napoleon and...

The pigs, the most intelligent of the animals, change the tenets of animalism to serve their own interests. For example, though the animals all agree that they won't ever live in a house or use a bed, the pigs insist that they "absolutely" must have the quiet of the farmhouse to think and plan, and when they use human beds, they initially justify it because they are not using sheets. They always have a handy rationalization for breaking or bending the rules.  

Napoleon says that the farm must engage in trade, though the animals had previously resolved never to trade. He justifies it as not for any "commercial purpose," but simply to obtain materials that the animals urgently need for building the windmill. When some of the animals suggest that this violates animalism, the dogs growl at them in an intimidating way and the sheep begin their mindless bleating of "four legs good, two legs bad." Here we see that fear and group thinking drown out dissent. The pigs will repeatedly use fear, especially fear of the dogs, and the sheep's propensity to mindless chanting, to exert control. Later, Squealer will insist that the animals had never agreed not to engage in trade or use money. He says that idea was probably a lie started by Snowball, who has been labelled the enemy of Animal Farm.

Most of the animals have integrity, believe in the tenets of Animalism, and want the farm to succeed. They want to believe their leaders have their best interests at heart. They are basically honest themselves, so it is hard for them to believe the pigs would lie so blatantly or put their own interests ahead of animalism. The pigs are craftier than the other animals, so they become skilled at twisting and shading the truth. They don't overturn the tenets of animalism all at once or adopt their privileges all at once. They move gradually, step by step, all the while doing everything they can to confuse the animals. Orwell is showing how humans can equally be deceived: the story is a warning against being too trusting and gullible.  

From Philbrick's Freak the Mighty, what are examples of times when Kenny Kane tries to be a good father to Max?

Kenny Kane kidnaps his son Max from the grandparents' house in chapter 16 of Philbrick's Freak the Mighty. From the onset, Kane continually tells the young teenager that Max's grandparents poisoned his mind against his father. These comments are Kane's way of trying to get Max to know that he cares about him, but it's not very effective coming from a kidnapper. Kane also vows that he never killed anyone. By informing his son that he isn't a killer, he is trying to comfort his son and make Max believe he is a good man. Additionally, Killer Kane discusses his plans to provide for his son and himself in the future in chapter 17. Trying to comfort Max and telling him his dad is a good man seems like ways that a good father would act.

Another way that Kane tries to show that he is a good father is by asking the following:

"Now the other thing is the geezers you've been living with all these years. I bet they never gave you the presents I sent you, did they?" (111).

This gesture seems nice, but there is no way of telling if Kane actually sent presents because Max never got them. If Kane did send Max gifts from prison, that would certainly be a sign that he has cared about his son all along. 

Kenny Kane also tells Max that he knows about Grim and Gram placing him in resource classes. Kane says that no child of his will ever be considered slow or challenged in any way. He simply advises Max to act smart, and he will be smart. Although uninformed about Max's educational situation, Kane does show a vote of confidence for Max that may have been unexpected. Good fathers do believe in their sons no matter what, so believing that Max is smart can also be an example of how Kane shows his son that he is a good dad.

What are some examples of minor conflicts in Harper Lee's To Kill a Mockingbird?

One example of a minor conflict in Harper Lee's To Kill a Mockingbird is the conflict between Scout and Calpurnia, which we can call a character vs. character conflict.

In the first chapter of the novel, Scout expresses adamant dislike for their cook Calpurnia. Calpurnia began working for the Finches shortly after Jem was born, and their mother passed away when Scout was only two; therefore, Calpurnia has been in Scout's life since she was born and has served as a surrogate mother for Scout, not just as a cook. Since Scout is young, she feels that every mothering remark from Calpurnia is antagonistic. As a result, Scout and Calpurnia fight a lot. Scout describes that their "battles were epic and one-sided" because Atticus always took Calpurnia's side. Scout further describes that she had "felt [Calpurnia's] tyrannical presence as long as she could remember," showing us just how much Scout dislikes Calpurnia at first.

However, this minor character vs. character conflict begins to be resolved as the novel progresses. As Scout begins to mature, Calpurnia is able to treat her differently. Calpurnia even invites Scout into the kitchen anytime Scout feels lonely as a result of Jem growing up. Scout particularly begins to see Calpurnia differently in Chapter 12 when Calpurnia brings Scout and Jem to her church. While walking home from church with Calpurnia, the children enter a conversation with Cal about why she talks grammatically with the Finches but ungrammatically when talking with members of her own race at church. Through Calpurnia's response, the children learn a lesson in humility that particularly influences Scout. It's at this moment that Scout decides she wants to spend more time with Cal to get to know her better and asks, "Cal, can I come to see you sometimes?" Cal responds by saying that Scout would be welcome at her home anytime she wishes, putting an end to the character vs. character conflict.

How do you define sociology?

Sociology is the study of social behavior. It encompasses the study of social groups, social interaction, and social institutions such as religion, government, and family. Sociology examines both how individuals behave within social institutions as well as how social institutions themselves change and transform through time.

Take, for example, the social institution of marriage. Sociology looks at how individuals behave within marriage. What are the motivations, choices, behavioral patterns, etc. of people within the institution of marriage? At another level, sociology asks about marriage itself. Why does marriage occur, what are its different forms, how has marriage changed through time, and why? In this way, sociology seeks to understand both individual and institutional dynamics. It also inquires into the relationship between the individual and the institution. Sociology asks how people shape and change social institutions, and how they themselves are shaped and changed by these institutions.

What is the immune system?

Structure and Functions

The immune system is capable of recognizing and identifying many different substances foreign to the human body. To function properly, this system must receive, interpret, and transmit large amounts of information about invaders from outside or within the body. These constant and ever-changing threats to the body must be met and destroyed by one complex system—namely, the human immune system. Many organs and parts of the body play a major role in maintaining resistance; some have more important roles than others, but all parts must work in unison. The circulatory and lymphatic systems, along with specific organs, are of primary importance in the overall workings of the immune system.

Blood. Besides the outer protective layer of the skin and mucous membranes, the first line of defense in the immune system includes the blood in the circulatory system. About 50 percent of human blood is made up of a fluid called plasma, which contains water, proteins, carbohydrates, vitamins, hormones, and cellular waste. The other half of blood is composed of white cells, red cells, and platelets. The red blood cells, called erythrocytes, are responsible for moving oxygen from the lungs to the other parts of the body. The special platelet cells, called thrombocytes, enable the blood to form clots, thus preventing severe bleeding. An unborn child produces red and white blood cells in the spleen and liver, while a newborn makes blood in the center of bones, called the marrow. After maturity, all red and most white blood cells are produced in the bone marrow. Although the red cells and platelets are vital, it is the white cells that play a major role in
the immune system.

In a broad sense, white blood cells surround and engulf foreign matter and adjacent dying cells in a process called phagocytosis. The function is possible since the white blood cells can move, unlike red corpuscles, by pushing their bodies out and pulling forward. Red corpuscles move because of the flow of the blood within the circulatory system. White blood cells move in the lymph vessels, where they work to defend the body against disease, but are also transported through the blood. Bacteria and other foreign material can remain alive within a white corpuscle, but sometimes the corpuscle dies from the toxins produced by the bacteria. The resulting formation of pus is actually an accumulation of dead white blood cells. At other times, the white corpuscles win and the foreign matter is destroyed.

Three major types of white blood cells, known collectively as leukocytes, are involved in immune responses. All three—granulocytes, monocytes, and lymphocytes—arise from areas in either bone marrow, the spleen, or the liver.

The granulocytes, each of which is about twice the size of a red blood cell, originate from red bone marrow and live only about twelve hours. Under the classification of granulocytes, distinct cells have different structures, sizes, and shapes. These specialized granulocytes include the neutrophils, eosinophils, and basophils. None of these cells has a specific memory for future immune responses. The neutrophil
granulocyte eats and digests small foreign matter with the help of special enzymes. Between 40 and 75 percent of the white blood cells in the human body are neutrophils. When these highly mobile neutrophil cells arrive at an injury site, they burst, releasing their enzymes and melting away the surrounding tissues. Eosinophils are similar to neutrophils but seem to be specialized in fighting infection caused by parasites, because of the seven toxic proteins that they use to fight. They are also effective against fungal, bacterial, viral, or protozoan
infections. Basophils, which are smaller in size, move from the bone marrow through the body and act as a control by preventing overreactions during an immune response. Basophils prevent coagulation, but they cannot destroy foreign matter. These cells account for less than 1 percent of the white blood cells found in the blood.

The second group of leukocytes includes the monocytes, the largest cells found in the blood. Monocytes are two to three times as large as red cells, yet they are not very numerous, making up 3 to 9 percent of all the leukocytes in the blood. After only a few days in the blood, they move to areas between tissues. Over the course of months or years, the monocytes enlarge ten times in size in order to specialize in phagocytosis. After this growth, they are called macrophages. They are also referred to as terminal cells since they cannot divide, and thus do not reproduce.

The third type of leukocyte, and the most sophisticated of the white blood cells, are called lymphocytes because they come from the lymph system as well as bone marrow. The T lymphocytes, which are primarily responsible for immunity, can change into helper, killer, and suppressor cells. Besides being able to recognize foreign matter precisely, they can live freely in the blood, grow larger and divide, and then change back to their original form after working against the invader. Lymphocytes circulate throughout the body, moving from the bloodstream through the lymph fluid and back into the blood. The two major types of lymphocytes are T lymphocytes (also called T cells) and B lymphocytes (also called B cells). Both T and B cells can recognize foreign matter and hook onto it. Some of these special “memory” cells remain in the body for life, preventing a specific invader from causing illness when it is encountered again in the future. These specialized cells must have a way to travel through the body; one of these transport systems is the lymphatic system.

The lymphatic system. This system is a closed network of vessels that help in circulating fluids from the body and returning them to the bloodstream. The
lymphatic system also defends against disease-causing foreign materials, known as antigens. The smallest components of the lymph system are the lymphatic capillaries that run parallel to the blood capillaries. The fluid inside these capillaries, which has come across the thin wall membrane from tissues all across the body, is called lymph. These capillaries merge into larger lymphatic vessels, which then merge into a type of collecting area called a lymph node. The lymph fluid is drained into trunks that join one of two collecting ducts. The larger left thoracic duct collects lymph from the lower part of the abdomen and the legs, and from the left side of the upper body before emptying into a vein near the neck and shoulder. The right lymphatic duct does the same for the right side of the upper body. After leaving the collecting ducts, the lymph fluid becomes part of the blood plasma in the veins and returns to the right atrium of the heart. Lymph does not flow like blood in veins and arteries; instead, it is controlled by muscular activity.

The spleen. This largest lymphatic organ is located in the upper left part of the abdominal cavity, behind the stomach and under the diaphragm. The hollow spaces within the spleen are filled with blood, making it soft and elastic. The white blood cells in the lining of these hollow cavities engulf and destroy foreign materials, as well as damaged red blood cells that pass through the spleen.

The thymus. This gland is located between the lungs and above the heart, just behind the upper part of the breastbone. It contains large numbers of white cells; some are inactive, but others develop and leave the
thymus to become functional in the immune system.

The liver. Located in the upper right part of the abdominal cavity below the diaphragm, the liver is well protected by the ribs. Since it is the largest gland in the body, it plays a major role in metabolism while also aiding the body’s ability to clot blood. In addition, various liver cells, called macrophages, help in destroying damaged red blood cells. The liver’s connection to the immune system is its ability to also destroy foreign substances through phagocytosis.

Bone marrow. Marrow is located in the center of bones. It can be divided into two types, red or yellow marrow. It is the red marrow that aids in the formation of white and red blood cells. The yellow marrow stores fat and is not involved in producing blood cells. Some white blood cells come from bone marrow cells. They are released into the blood and are carried to the thymus gland, where they undergo special processing that changes them into T lymphocytes (the letter T shows that they came from the thymus gland). The other lymphocytes that do not reach the thymus after leaving the bone marrow are named B lymphocytes (B because they came from bone marrow). These B lymphocytes are abundant in lymph nodes, the spleen, bone marrow, secretory glands, intestinal lining, and reticuloendothelial tissue.

The Responses of the Immune System

Failures of the immune system can lead to devastating diseases, either because the immune system attacks itself or because it fails to defend against outside foreign antigen matter. An antigen can be any substance that stimulates the body to fight, ranging from a bacterial infection to the virus that causes acquired immunodeficiency syndrome (AIDS).

When the body fights against an antigen, the immune system can produce two types of response, either a cellular immune response or a humoral immune response. The cellular response involves specific types of cells that recognize, attack, and destroy the invading pathogen or antigen. It is the primary response against most viruses, many fungi, parasitic organisms and some bacteria (for example, mycobacteria), and against transplanted tissues. The humoral immune response, which consists of complement and antibodies, is the body’s main defense against most other bacteria. The two systems work together, however, communicating by complex chemical mediators.

Another way of looking at how the body fights to keep itself healthy is to separate the immune responses into either primary or secondary responses. The second time that a given antigen enters the body, the immune system attacks with what is called the secondary immune response stored in special immune memories, making it faster and more extensive than the primary response that occurred when the antigen was first encountered. This immune memory must be built for each antigen before the body becomes immune to the wide variety of diseases and conditions to which one is exposed on a daily basis.

The body begins to build this memory prior to birth by making an inventory of all the molecules within the body. Foreign substances not in this memory are considered to be antigens, which will activate an immune response. When an antigen is first encountered, the primary response occurs, producing lymphocytes that are sensitized to the invader. Many types of lymphocytes can respond in order to create the appropriate antibody molecules, which are then released into the lymph and transported to the blood. This process may last several weeks. During this primary immune response, the B cells and T cells serve as memory cells. Because a memory for the antigen has been stored, if this antigen is encountered in the future the memory cells can react more quickly and effectively. In this secondary immune response, the antibodies are ready to react by attaching themselves to the surfaces of the antigens. There must be a specific type of antibody produced for every type of antigen. These new antibodies may survive only a few months, but the memory cells live much longer.

There are four main ways that an antibody can bind to an antigen. The antibody can pull together clusters of invading organisms to prevent the antigens from spreading. Another possibility is for this special component of the blood to punch a hole in the invader and destroy it. The antibody can also combine with the antigen, which makes it easier to destroy. In the case of a virus or a toxin, the antibody can neutralize the harmful activity by covering the outside of the antigen. With so many ways for an antibody to attach to an antigen, it is equally important for the antibody memory to be established. It is this special memory that leads to future immunity.

These memory cells are responsible for the four different types of immunity, two of which are acquired actively and two of which are acquired passively. The first type is naturally acquired active immunity, which results after the body is exposed to a live pathogen and develops the disease. The second type is artificially acquired active immunity, such as that gained after a vaccination. The immune response is triggered after an injection of weakened or dead pathogens is received, but the body does not suffer the severe symptoms of the disease. An example would be a smallpox vaccination. The third type of immunity is artificially acquired passive immunity, gained through an injection of prepared antibodies. This method is considered passive since the antibodies, called gamma globulin, were made by another person. This type of immunity usually does not last more than a few weeks, and the person will be susceptible to that pathogen in the future. Naturally acquired passive immunity occurs when the antibodies pass to the fetus from the mother, but it includes only
those antibodies available in the blood of the mother. This process gives an infant certain short-term immunities for the first year of life.

These types of immunity are usually desirable, but there are occasions when an immune response is not wanted, such as after an organ transplant. When tissue or organs are transplanted from one person to another, the body may reject the foreign tissue, triggering an immune response and possibly destroying the new organ. Consequently, attempts are made to match the tissue between recipient and donor. In an effort to halt the immune response, immunosuppressive drugs are given to interfere with the recipient’s ability to form antibodies, and drugs can be administered to destroy the lymphocytes that produce these antibodies. Unfortunately, the recipient is often left unprotected against infections, since the immune system is not functioning normally.

Perspective and Prospects

In the same way that the discovery of penicillin shocked the world,
immunology has created endless possibilities in medicine. When surgeons found that they could transplant an organ from one person to another, the interest in immunology exploded.

This field of medicine has discovered that the immune system’s power and effectiveness can be lessened because of several factors. Improper diet, stress, disease, and excessive physical activity levels can depress the immune system. Other factors that can modify immunity include age, genetics, and metabolic and environmental factors. The anatomical, physiological, and microbial factors are shown in the susceptibility of the young and the very old to infections. For the young, the system is immature, while the aged have suffered a lifetime of assaults from pathogens. The impact of psychological stress is difficult to measure, yet it holds the potential for negatively affecting the immune system.

Before immunology can be fully understood, more knowledge must be gained about how antibodies are made and how they develop memories. Lymphocytes must be examined to discover what role they play in the immune response. Studies must look at not only the whole picture of the immune system but also its smaller parts—the organs and how each participates. Such studies could lead to better success in transplanting these organs. Unanswered questions remain about how the immune system relates to other body systems. The relationships among the brain and nervous system, hormones, and the respiratory system leave many areas ripe for further study.

Recent research has identified the significant importance of Class I major histocompatibility proteins (I-MHCPs) in the cellular immune system. When disease-associated proteins occur in a cell, they are broken into pieces by the cell’s proteolytic machinery. Cell proteins become attached to antigen fragments and transport them to the surface of the cell, where they are “presented” to the body’s defense mechanisms. I-MHCPs are these transport molecules. The I-MHCPs holding an antigen fragment can attach to certain immature T cells. Once such a T cell and I-MHCP-antigen complex hook up, the T cell reproduces many times. This important link between the cellular immune system and I-MHCPs has been shown in recent times by the epidemic of diseases like AIDS, which kills T cells. Class II MHCPs (II-MHCPs) interact similarly in antibody production by the humoral immune system. Understanding of the genes used in production of the I-MHCPs and the II-MHCPs has led to great hope for methods to control their production, possibilities for eventual cure of AIDS, emerging
cancer treatments, and better understanding of the production of antibodies.

Additional information is needed on defects in the system, as are explanations for its dysfunctions. With greater knowledge of immunology, it may be possible to conquer AIDS, allergies, and asthma and to develop birth control methods based on the immune response. Doctors may be able to cure cancer, diabetes, herpes, infertility, multiple sclerosis, and rheumatoid arthritis. The possibilities are endless and could also include perfecting transplants of organs and skin grafts and preventing birth defects and even obesity. Through human gene therapy, those at risk for genetic disorders could be diagnosed and those with existing genetic conditions could be treated. Genetically engineered drugs and gene replacement therapy could relieve the stress on the human immune system. Until these methods become feasible, however, individuals must protect the natural immunity supplied by their bodies.

Bibliography

Adelman, Daniel C., et al., eds. Manual of Allergy and Immunology. 5th ed. Philadelphia: Lippincott Williams & Wilkins, 2012.

Delves, Peter J., et al. Roitt’s Essential Immunology. 12th ed. Malden, Mass.: Blackwell, 2011.

Frank, Steven A. Immunology and Evolution of Infectious Disease. Princeton, N.J.: Princeton University Press, 2002.

Immune Web. http://www.immuneweb.org.

Hawley, Louise, Richard J. Ziegler, and Benjamin L. Clarke. Microbiology and Immunology. Philadelphia: Lippincott Williams & Wilkins, 2013.

Janeway, Charles A., Jr., et al. Immunobiology: The Immune System in Health and Disease. 7th ed. New York: Garland Science, 2007.

Kuby, Janis, et al., eds. Kuby Immunology. 7th ed. New York: W. H. Freeman, 2013.

Life, Death, and the Immune System. New York: W. H. Freeman, 1994.

Male, David K., et al., eds. Immunology. Philadelphia: Elsevier/Saunders, 2013.

Marieb, Elaine N. Essentials of Human Anatomy and Physiology. 10th ed. San Francisco: Pearson/Benjamin Cummings, 2012.

Tortora, Gerard J., and Bryan Derrickson. Principles of Anatomy and Physiology. 13th ed. Hoboken, N.J.: John Wiley & Sons, 2012.

How do Jem and Scout differ in their opinions about what to do with the intruder in Chapter 14 of Harper Lee's To Kill a Mockingbird?

By the end of Chapter 14 of Harper Lee's To Kill a Mockingbird, Scout and Jem discover Dill, an intruder, hiding under Scout's bed. Jem and Scout clearly disagree about how to handle their unexpected visitor. Jem believes that adults should know, whereas Scout indicates she only wants to protect her own and Dill's interests.

Dill had run away from Meridian, wanting to be in Maycomb, and had been hiding under Scout's bed, filthy and hungry. When they finally discover him, Scout brings him a pan of leftover cornbread, and Dill relays his adventures. Then, Jem, acting very grown up, says, "You oughta let your mother know where you are ... You oughta let her know you're here." He then leaves the room and asks Atticus to come to Scout's room.

Scout expresses having felt betrayed by Jem's action, for she describes him as having broken the "remaining code of our childhood." She also says she "felt sick," which shows she is worried about how Atticus will respond to finding Dill there and would have preferred not to have informed Atticus in order to prevent Dill from being sent back to Meridian. Scout had been heartbroken to learn by letter that Dill would not be permitted to go to Maycomb that summer because he was expected to spend time with his new stepfather. Therefore, Scout wants Dill there in Maycomb just as much as Dill wants to be there, and she would do anything to keep him there.

This contrast in Scout's and Jem's actions shows that Jem is old enough to worry about doing the right thing, whereas Scout, still being very young, only thinks of personal interests.

What is tommy john surgery?

Tommy John surgery is a medical procedure during which the ulnar collateral ligament (UCL) in the elbow is removed and replaced with a transplanted tendon. In most cases, the surgery becomes necessary when the UCL becomes damaged or torn as the result of repetitive strain. While anyone can find themselves in need of Tommy John surgery, the procedure is mostly associated with athletes, especially baseball players and pitchers in particular.

Historical Context

Tommy John surgery was pioneered by Dr. Frank Jobe, an orthopedic surgeon who founded a practice in the Los Angeles area in the 1960s. Early on, he and partner Dr. Robert Kerlan formed a working relationship with the Los Angeles Dodgers—the local Major League Baseball franchise—and began providing services for players such as legendary pitcher Sandy Koufax. In this capacity, Jobe quickly learned that proper functionality of the elbow and its anatomical components was of critical importance to athletes such as Koufax who relied heavily on their ability to throw balls or other objects. He also noticed that injuries to the UCL were particularly problematic for such athletes, often ending their careers.

Eager to find an effective means of addressing UCL issues, Jobe noted the success surgeons were having in restoring the functionality of injured fingers through the transplantation of certain ligaments and wondered whether a similar approach might work for the elbow. After carefully developing an experimental surgical procedure for replacing the UCL with a transplanted tendon, Jobe needed a suitable candidate willing to be a test subject. That candidate was Tommy John, a Dodgers pitcher who had likely been throwing with a damaged UCL his entire career. Hoping to avoid an early retirement, John agreed to undergo Jobe's experimental surgery in July 1974. Although his subsequent recovery prevented him from returning to the field for an entire season, the surgery was a success and John was ultimately able to continue playing until 1989. In recognition of being the first person to undergo the operation, John became the honorary namesake of Jobe's revolutionary procedure.

The Procedure

Formally known as UCL reconstruction, Tommy John surgery is a relatively noninvasive surgical procedure used to treat patients who have damaged or torn a UCL because of repetitive extreme stress. By removing the damaged UCL and replacing it with a transplanted tendon, surgeons can restore functionality and afford patients relief from pain.

To perform a Tommy John procedure, the surgeon first extracts a substitute tendon from another part of the patient's body or from a cadaver. These tendons can be taken from a number of places, including the forearm, knee, hamstring, hip, or foot. The most commonly used replacement tissue, however, is the Palmaris, a redundant tendon found in the wrist. Once the replacement tendon is secured, the surgeon removes the damaged UCL and drills holes in the humerus (upper arm bone) and the ulna (a lower arm bone). Next, the surgeon passes the tendon through the holes in a figure-eight pattern and attaches the ends of the tendon to the remaining portions of the original UCL. Finally, the incision is closed and the surgery is completed.

More often than not, Tommy John surgery does not carry a significant risk of complications. Only 5 to 20 percent of patients who undergo the procedure experience any sort of significant problems afterward. The most common issue associated with Tommy John surgery is ulnar nerve damage, but infection can also occasionally occur.

Recovery

While Tommy John surgery itself usually takes only about an hour to complete, the patient's recovery period is a much longer process that often requires about a year of rehabilitation and physical therapy. Following surgery, the patient's elbow is typically immobilized for anywhere from one week to ten days. During that time, the patient can engage in gentle range-of-motion activities as well as light arm and shoulder strengthening exercises. After about four to five weeks, athletes who have undergone Tommy John surgery can resume throwing balls, although they are usually advised to avoid windups. At six weeks, most patients can begin to work on strengthening the affected elbow itself. Most pitchers begin throwing normally again after seven months. From there, the recovery timetable depends largely on the individual and the specifics of his or her condition. For pitchers who are no longer experiencing pain and have regained full range of motion, it may be possible to return to full competition in as little as nine months. For others, complete rehabilitation may take longer.

Success and Controversy

Since Jobe first operated on Tommy John himself, the surgery has become a widely accepted medical procedure that has helped countless athletes to overcome debilitating UCL injuries and extend their careers. For baseball in particular, Tommy John surgery has been especially significant. By allowing elite pitchers to remain on the mound as long as possible, Tommy John surgery has increased competitiveness and improved the quality of play at virtually every level of the game. Indeed, many of baseball's greatest modern pitchers, including Joba Chamberlain, Stephen Strasburg, and Brian Wilson, have benefitted from the procedure.

The effectiveness of Tommy John surgery, though undoubtedly great for baseball, has also led to controversy at the sport's lower levels. Seeing how the procedure has improved the performance of the players who have had it, some parents of underperforming Little Leaguers have sought to give their children a competitive boost by putting them through the surgery even though they do not have UCL injuries. Numerous physicians, including Jobe, have refuted the usefulness of this sort of strategic Tommy John surgery, however, arguing that while the procedure may appear to improve performance, it is really only returning players to the skill level they were at before they were injured.

Bibliography

Ansorge, Rick. "Tommy John Surgery." WebMd. WebMd, LLC. 11 Feb. 2014. Web. 19 Mar. 2015. http://www.webmd.com/fitness-exercise/tommy-john-surgery-ucl-reconstruction?page=1

Carroll, Will. "Dr. Frank Jobe, Tommy John, and the Surgery That Changed Baseball Forever." Bleacher Report. Turner Broadcasting System, Inc. 17 July 2013. Web. 19 Mar. 2015. http://bleacherreport.com/articles/1672080-dr-frank-jobe-tommy-john-and-the-surgery-that-changed-baseball-forever?utm_source=cnn.com&utm_medium=referral&utm_campaign=editorial&hpt=hp_t3

Carroll, Will. "Tommy John Surgery: The Realities and Myths of Sports' Most Famous Operation." Bleacher Report. Turner Broadcasting System, Inc. 17 July 2013. Web. 19 Mar. 2015. http://bleacherreport.com/articles/1675444-tommy-john-surgery-the-realities-and-myths-of-sports-most-famous-operation

Dodd, Mike. "Tommy John Surgery: Pitcher's Best Friend." USA Today. Gannett Company, Inc. 28 July 2003. Web. 19 Mar. 2015. http://usatoday30.usatoday.com/sports/baseball/2003-07-28-cover-tommy-john_x.htm

What are the differences between food chains and food webs?

A food chain represents the pathway of the transfer of food and energy in an ecosystem through different organisms. There is only a single pathway in a food chain, which means that an organism is dependent on the organism on the lower trophic level for food and energy (for example, deer is dependent on grass) and cannot get its energy elsewhere. In comparison, a food web consists of a number of interconnected food chains and thus, each organism is part of a number of food chains. This results in multiple pathways for transfer of food and energy and ensures that each organism can receive food and energy from different organisms. 

A food chain is very simple, while a food web is complex. Also, the removal of organisms at any trophic level will destroy the food chain, whereas the same is not true for a food web, since organisms are a part of different interconnected food chains. 

Hope this helps. 

What is society's main purpose according to Ralph Waldo Emerson in "Self-Reliance"?

Emerson contends that society is "a joint-stock company" that is in conspiracy against the individual.

According to Emerson, society's main purpose is to suppress individuality:

Society everywhere is in conspiracy against the manhood of every one of its members. 

Emerson, who rails against conformity in his essay, states that the "joint-stock company" of society has members who agree to relinquish their individualism for the safety of conformity. They, then, share the same opinions, the same thoughts, and they want others to accept these opinions and thoughts.

In his essay, Emerson makes a persuasive argument for non-conformity and self-sufficiency. Finding sanctity in the individual mind, he calls upon those in his audience to express themselves strongly. Further, he insists that imitation of others is ignorance, and in the individual's mind there is sanctity. For, Emerson contends, the divine presence is at work in those who would be individuals. After all, he concludes, only by being non-conformists can people be fully human.

With consistency a great soul has simply nothing to do. He may as well concern himself with his shadow on the wall.

Finally, Emerson concludes by stating that acting in accordance with true feeling will effect a sound, worthy life. And, he states, it matters not that a person be misunderstood because many great people such as Pythagoras, Socrates, Jesus, Luther, Copernicus, and Galileo were misunderstood. After all, "[T]o be great is to be misunderstood...."

What does the word "double" signify in Macbeth?

There are a number of words that appear obviously as motifs in Macbeth (blood, sleep, etc.). The word "double" is also a motif, though it doesn't seem to get quite the amount of attention that other, more concrete/tangible words get in analysis. 

The word "double" appears in both literal and abstract form in the play. It appears literally when the witches describe their plans: "Double, double toil and trouble" (Act 1, Scene 1), where they mean to literally double the trouble that is about to happen. First, they use the word twice (doubling it); the punctuation of the sentence makes the word appear as a repetitive device. Also, the witches are troublemakers, and they like to cause as much difficulty for their targets as possible. By doubling, in this case, Macbeth's trouble, they get to experience double the amount of glee at watching the consequences.

Another literal use is from the Captain as he describes the battle in Act 1, Scene 2. "As cannons overcharged with double cracks / So they doubly redoubled strokes upon the foe." This helps to show the force and height of the battle: the cannons were packed with double the ammunition, and the soldiers "doubly redoubled," meaning they possibly quadrupled their physical efforts (shots, stabs, etc.) on the opposition.

Beyond the literal meanings, the word "double" has an abstract meaning as well that contributes to one of the main themes of Macbeth: the idea that things are not as they seem to be. More specifically, the word suggests that, though Macbeth appears to act with confidence, he actually spends the entire play becoming weaker and more dependent on those around him. 

"He's here in double trust," Macbeth says to describe King Duncan and his visit to Inverness in Act 1, Scene 7. This shows that Macbeth is already feeling guilt, though his actions suggest otherwise. It's impossible to "double trust"; either you trust someone, or you don't. Though Macbeth tries to use the word, in this case, literally (Duncan sees Macbeth as both a subject and as a host), the subtext suggests Macbeth is actually feeling twice the guilt over what he is about to do.

This idea continues toward the conclusion of the play (Act 4, Scene 1) when Macbeth makes the decision to kill MacDuff. "Then live, Macduff. What need I fear of thee? / But yet I’ll make assurance double sure, / And take a bond of fate." There is no need to touch MacDuff; he is not a threat to Macbeth's future. Yet, Macbeth is now mired in the witches' prophecies so deeply, he's compelled by guilt and dependence on the witches' words to "make double sure." (Again, like trust, one cannot be "double" sure; you're either sure, or you're not).

Though other words in Macbeth often receive more attention for their literal, concrete qualities, the word "double" contributes significant meaning to the play; looking for recurrences of this word can double the reader's enjoyment and understanding of the text. 

What is the relationship between dissolved oxygen content and fish populations in the body of water?

Dissolved oxygen represents the oxygen gas that is dissolved in water. Fish and other aquatic species need this oxygen for their survival. Fish have specific organs for this purpose. 

From the given data, we can see that dissolved oxygen (DO) is necessary for fish. At 0 ppm DO concentration, there are no fish. In fact, even at 2 ppm DO level, there is only 1 fish. The fish population starts increasing beyond a DO level of 4 ppm, reaching a maximum value of 15 at 12 ppm DO. There is an increasing trend in the fish population up to a DO value of 12 ppm; then it falls and then rises again. 

In general, DO is necessary for fish survival and a minimum value of about 6 ppm is required for a significant fish population. 

Hope this helps. 

What made Oedipus go insane?

Oedipus scratches out his own eyes when he discovers that he has fulfilled the prophesy of the Oracle of Delphi, who told him that he would kill his own father  and marry his mother. Oedipus had not known that the old man he had fought with and killed while on the road to Thebes was his father, Laius, and that he married his mother, Jocasta, unwittingly. Years before, after hearing his prophecy, Oedipus had assumed that his father and mother were the man and woman who had raised him, when in fact King Polybus and Queen Merope were his adopted parents, who had taken him in from shepherds who discovered him as an infant, after his father had ordered him executed.

Oedipus realizes all of this too late, after his mother and wife, Jocasta, figures  out what has happened and hangs herself in a frenzy of grief and disgust. So what really drives Oedipus to scratch out his own eyes is the confluence of events of Jocasta's suicide, and the realization that he has unwittingly fulfilled the prophecy that he fled his home to avoid. This cruel irony and the revulsion Oedipus feels at knowing that he has been making love to his mother for years, cause him to scratch his eyes out.

Yet I would caution the reader against assuming that Oedipus' reaction means that he "lost his mind." The situation he finds himself in is horrific and extraordinary. Some might argue that Oedipus' incredibly violent and self-destructive reaction to the discovery that he has committed regicide, patricide and incest, is entirely proportional, and not an over-reaction. In the context of a Greek tragedy, this catharsis is not a signal of psychosis, but an epic punishment that fits a truly epic and tragic crime.

What are three reasons why we feel sympathy for Macbeth at the end of the play?

One reason we might feel sympathetic for the villainous Macbeth at the end of the play is the fact that he has clearly been manipulated by the witches. By revealing to him a series of half-truths, they have goaded him into destroying everything around him, including himself. When he realizes that their prophecy that only a man "not of woman born" could kill him was in fact about to be fulfilled by Macduff, who was born by Caesarian section, he knows that he has been duped. 

Another reason we might feel sympathy for Macbeth is that once he realizes he is not, as he thought, invulnerable, he still resolves to go down fighting. There is no doubting his bravery as he compares himself to a bear tied to a stake, forced to fight to the death.

Finally, we recall at the beginning of the play that Macbeth was a good, honest, loyal thane. At the end of the play, as the witches' prophecies come true (after a fashion) we find ourselves asking whether Macbeth was perhaps the victim of malevolent forces beyond his control. It seems possible that his death was fated, or made inevitable by the witches themselves. So even more than a dupe, Macbeth could be interpreted as a victim at the end of the play, albeit in a different sense than his own many victims.

How is the theme of happiness portrayed in the novel Fahrenheit 451?

In Fahrenheit 451, happiness is a problematic and elusive concept. For the majority, censorship is the source of happiness because people focus their energies on entertainment and not on the thought-provoking subjects found in books.

But this is not as straightforward as it first appears. Take Mildred, for example. She seeks solace in the 'Family' and the parlor walls, but her suicide attempt in Part One suggests that, deep down, she is miserable. Her reluctance to face this fact also results in her violent death, as imagined by Montag in Part Three, when she realizes the emptiness of her existence:

She saw her own face reflected there...and it was such a wildly empty face...touching nothing, starved and eating of itself.

In contrast, at the beginning of the novel, Montag believes that he is happy because his life appears perfect: he is married, enjoys his job and is financially well-off. But his meeting with Clarisse makes him question this:

He was not happy. He said the words to himself…He wore his happiness like a mask.

In other words, through Montag and Clarisse's relationship, Bradbury is suggesting that happiness is about more than security and materialism. Being happy is about having the freedom to think for yourself and question the world. Without this, we are nothing more than empty robots. 

What are some problems facing students and teachers learning/teaching English as a second language which might be suitable for a research paper?

Here, I am assuming that you are referring to Teaching English as a Second Language (often abbreviated as TESOL). 

Research papers in this subject tend to be narrowly focused studies emphasizing a particular group of language learners or a particular pedagogical approach; they rarely address multiple problems at a range of levels. Although a PhD thesis or a book might cover multiple stages in English learning, a research paper would either focus on a single learning stage or compare and contrast how to teach a very narrow skill to students at different stages in their learning. For example, you might compare errors in article usage in first and second year Chinese students studying English in one particular program. 

Another possibility might be to look at how to apply different pedagogical techniques to teach the same material to students at different ages or learning stages. For example, you might look at different methods for teaching a single irregular verb such as "to be" to native speakers of German beginning English in secondary school versus ones starting English studies at the university level. 

Your key to a successful paper is to choose a very narrow topic which you can examine in great detail rather than trying to cover a large amount of material in a more superficial manner.

How did George Bush carry out the 9/11 attacks without the people's permission?

The most important answer to this question is that the question itself assumes a “fact” that is not true.  The question assumes that President Bush was behind the terrorist attacks of September 11, 2001.  This is a complete falsehood.  There are, of course, many conspiracy theories that say that the 9/11 attacks were not really devised and carried out by Islamist terrorists.  However, there is no evidence that these conspiracy theories are actually true.  There are at least two reasons why these are ridiculous.  First, it is inconceivable that the American government would commit such an act against its own people.  It is true that the government has done bad things in the past, but these acts were committed against foreigners or against minorities within the country.  There is no example of the government ever killing thousands of random Americans while doing something that would make the US look weak and vulnerable.  Second, it is even less credible that the government could carry out and then cover up such an operation.  The American government is well-known for being unable to keep secrets.  This operation and cover up would have taken thousands of people to pull off.  How is it that, almost 15 years later, no one has come forward to talk about how they were part of the conspiracy?  So, this question assumes as fact something that is completely outside the realm of possibility.

Now, if Bush had ordered these attacks, the US governmental system makes it easy for presidents to do some things “without the people’s permission.”  The president has control over the executive branch, which includes the military and many other government agencies that could have had a hand in a conspiracy like this.  The president does not need the permission of the people to order military personnel and other government officials to do various things.  Therefore, if Bush had wanted to do something like this, he would not have needed “permission.”

However, Bush did not order the attacks.  This is a conspiracy theory that still exists, but it is one that has no basis in truth.

What was the Columbian Exchange?

The Columbian Exchange was the biological exchange that took place between the Old and New Worlds during the Age of Discovery. From the Old World, the New World received vegetables such as potatoes, tomatoes, and corn. These crops increased longevity and birth rates in the Old World and helped to create the surplus population that would later go to the New World. The Old World also received tobacco from the Caribbean and Virginia. This cash crop would be quite valuable and soon became both a scourge (in terms of health benefits) and benefit (as currency) worldwide.  

The New World received wheat from the Old World—a few grains of wheat at a Spanish mission would grow into a multi-million dollar granary for feeding the Spanish Empire. Cattle and hogs from the Old World destroyed native garden plots, leading to war between natives and whites. The New World also received diseases such as smallpox and diphtheria which would kill up to ninety percent of the Pre-Columbian population.  

What is the recommendation in The Story of My Life?

Captain Keller, Helen's father, sought help from Mr. Anagnos of the Perkins Institution.  Helen's father desired to find a teacher who could help his deaf and blind little girl.  Mr. Anagnos recommended Miss Anne Sullivan.  Miss Sullivan had suffered from partial blindness, but her sight had been restored through surgery.  Mr. Anagnos later said that "she showed from the very start that she had in herself the force and capacity which insure success."  

Dr. Howe's research and findings helped Miss Sullivan to prepare for the challenges of teaching Helen.  She had also occupied the same house as Laura Bridgman for several years.  Laura Bridgman was deaf and blind and had learned to communicate.

The recommendation of Miss Sullivan by Mr. Anagnos turned out to be an excellent one.  She worked tirelessly and with determination as she taught Helen.  The child soon was communicating and learning.  Miss Sullivan remained Helen's teacher and companion for the rest of her life.

In David Rabe’s The Basic Training of Pavlo Hummel, what does Hummel’s “basic training” consist of? Rabe is also talking about...

In David Rabe's "The Basic Training of Pavlo Hummel", the notion of training encompasses both physical conditioning and a symbolic rite of passage. Since war is an inevitable and perpetual feature of human society, the metaphorical experience of 'basic training' is a universal one; since the machine of war requires violence and brutality, its success hinges on the cold, calculated will to destroy and kill. As such, the brand of soldier Rabe depicts as created during basic training is an ultra-masculine, emotionally disconnected, cynical one. Through force of coercive language (military chants, barked orders), exercises (push-ups and drills) and dogma (pushing through the pain of injuries), represented by characters like Sergeants Tower and Wall, Hummel and the other soldiers gradually lose any naïveté and open-mindedness as they transform into tough, heartless cynics. In Hummel's desperate and pathetic attempts to be accepted by his peers and earn the approval of commanding officers, his confusion is compounded by his efforts to fit the military mold; questions of individual will and responsibility are supplanted by the desire to conform. Thus, the ultimate purpose of basic training is to suppress the needs and wishes of the individual in order to allow institutional aspects of war to dominate.

What are Chiari malformations?

Causes and Symptoms

Primary or congential Chiari malformations are a result of structural flaws during fetal development of the brain
of spinal canal. The classification of Chiari malformations into four types is based on the extent of the structural flaws. Chiari malformations may also occur after surgery of the head and neck area or after an injury; they are considered secondary or acquired Chiari malformations.

Some individuals with type I do not have any symptoms and may not even know they have a Chiari malformation. This type is considered the adult form of the disorder because often symptoms first appear in adolescence or adulthood. Headaches, neck pain, balance problems, dizziness, hearing and vision problems, and numbness in the arms and legs are the symptoms that result from the pressure on nerves caused by the herniation of the cerebellum into the foramen magnum; the symptoms may come and go. A secondary condition called a syringomyelia may develop in some cases, and it can cause permanent nerve damage.

Type II, also known as an Arnold-Chiari malformation, is considered the classic Chiari malformation. In this type, both the cerebellum and part of the brain stem are pushed into the foramen magnum. Type II is a pediatric disorder, and it almost always involves a form of spina bifida.

Types III and IV, also pediatric disorders, are the most serious forms of Chiari malformations and involve significant brain and neurologic defect. Children with these types do not usually live past two years of age.

Treatment and Therapy

Treatment is not necessary for those individuals who do not have symptoms. Otherwise, treatment is based on the severity of the disorder. Pain medications or nonsteroidal anti-inflammatory drugs (NSAIDs), or both, are used to reduce the pain.

Surgery, specifically some type of decompression surgery, is used to alleviate the pressure on the spinal cord and nerves. Various surgical procedures may be performed to reduce pressure by making more room. One frequently used procedure is a posterior fossa decompression, in which a small piece of the skull at the back of the head is taken out; sometimes a piece of synthetic tissue, called a dura patch, is used to enlarge the area for the brain. Another surgical procedure that is used to relieve pressure and make more room is a laminectomy, in which some of the bony border of the spinal canal is removed.

Other surgical procedures, such as insertion of a shunt for drainage of a syringomyelia or surgical closure of the spinal column in spina bifida, may be necessary. Some surgeries for treatment of the pediatric forms of the disorder are done before birth.

Surgery does not cure Chiari malformations, and it cannot undo the nerve damage that has already occurred. Nevertheless, the various surgical procedures can reduce the pressure and relieve the symptoms. Surgery is not always effective, however, and it is possible that a more severe Chiari malformation may result after surgery.

Bibliography:

McCoy, Krisha. "Arnold-Chiari Syndrome." "Health Library, Sept. 30, 2012.

National Institute of Neurological Disorders and Stroke. "Chiari Malformation Fact Sheet." NINDS, Apr. 18, 2013.

Novegno, F., M. Calderelli, A. Massa, et al. “The Natural History of Chiari Type I Anomaly.” Journal of Neurosurgery Pediatrics 2, no. 3 (September, 2008): 179–87.

Oakes, W. Jerry, and R. Shane Tubbs. “Management of the Chiari Malformation and Spinal Dysraphism.” In Clinical Neurosurgery, edited by Guy M. McKhann. Denver: Lippincott Williams and Wilkins, 2004.

Parker, James N. The Official Parent’s Sourcebook on Chiari Malformations. San Diego, Calif.: Icon Health, 2003.

What are inhibitory and excitatory impulses?

Introduction

An unstimulated neuron
—one that is neither receiving nor transmitting an impulse—maintains a difference in ions on either side of its cell membrane. While many positively charged potassium (K+) ions are present within the cytoplasm of a cell, proteins and other large molecules located there carry more numerous negative charges, making a negative net charge inside the membrane. Large numbers of positively charged sodium ions (Na+) are located on the outside of the cell in the intercellular space, giving it a net positive charge. Thus, in a resting neuron, there is a positive charge on the outside of the cell membrane and a negative charge on the inside. This charge difference is called the resting membrane potential. It is usually expressed as 70 millivolts, meaning that the inside of the cell is seventy thousandths of a volt more electrically negative than the outside.

The resting membrane potential is maintained by active transport of ions across the cell membrane. Sodium and potassium ions move across the membrane by diffusion, with sodium leaking into the cell and potassium leaking out. These ions are said to be moving down their concentration gradients, going from an area of higher concentration of each ion to an area of lower ion concentration. Such movement occurs passively, without the addition of energy by the cell. If this movement were allowed to continue uninterrupted, the resting potential would be lost fairly quickly, as the ions would reach equilibrium where they would be at the same concentration on both sides of the membrane. This is prevented from happening by the active transport process of the sodium-potassium pump. Active transport is a means of moving materials across the cell membrane from an area of lower concentration to an area of higher concentration. It cannot occur by diffusion, but requires the input of energy from the cell, released by breakage of a molecule by adenosine triphosphate (ATP), the energy currency of the cell. The sodium-potassium pump is a protein that spans the cell membrane and acts as a channel through which both sodium and potassium are pushed against their concentration gradients by the cell’s energy. Much of the ATP made by every cell is used to run this pump and maintain the resting potential, not only in neurons but in all other cells as well. The sodium-potassium pump moves two potassium ions into the cell and three sodium ions out of the cell for each ATP molecule broken.

Process of Information Transmission

The electrical difference between the sides of the cell membrane is particularly important in neurons, since it is through a change in this difference that a message is passed along the surface of a single neuron. In this information transmission, an electrical impulse passes down an excited, activated neuron’s axon (the single fiberlike extension of a neuron that carries information away from the cell body toward the next cell in a pathway) to the “output” end of the cell, the axon terminal. There the electrical impulse causes tiny vesicles or sacs filled with a chemical called a neurotransmitter to move to the cell membrane and fuse with it, emptying the contents of the vesicles into the space between cells, which is called a synapse. The cell that releases its chemical messengers at the synapse is the presynaptic neuron, and the cell that receives the message is the postysynaptic neuron. The message of the neurotransmitter is received by the second cell when the chemical binds to a protein receptor on the surface of the postsynaptic cell, usually on a dendrite (a branching extension of a neuron through which information enters the cell) or the cell body. This message may be interpreted as an excitatory stimulus or as an inhibitory stimulus. Either kind of stimulus causes a change in the properties of the receptor and of the postsynaptic cell to which it belongs, generally by changing the permeability of the cell’s membrane.

Excitatory Stimulation

When the stimulus is excitatory, the charge difference on the two sides of the membrane is at first lowered. A threshold level of electrical charge is reached, about 55 millivolts, and an action potential—a rapid change in electrical charges on a neuron’s cell membrane, with depolarization followed by repolarization, leading to a nerve impulse moving down an axon—is generated, followed by the firing of the neuron. A self-propagating wave of depolarization results from an excitatory stimulus that causes the neuron to reach threshold. Depolarization can be defined as a shift in ions and electrical charges across a cell membrane, causing loss of resting membrane potential and bringing the cell closer to the action potential. Special proteins called sodium gates open in the cell membrane, forming a channel that allows sodium ions from outside the cell to flow rapidly down their concentration gradient into the cell’s interior. As the net charge inside the cell becomes positive, the charge outside the cell becomes negative. There is a sharp rise, then a decline of the charge within the cell, called a spike, that reaches as high as 35 millivolts with the inflow of sodium ions. The action potential that results from this entry of ions acts according to the all-or-none law. A neuron will either reach the threshold and respond completely or will not reach the threshold and will not respond at all; there is no partial response. After sodium ions rush into the cell, the sodium gates close and the potassium gates open, allowing potassium ions to flow out of the cell, restoring the negative charge inside the cell. The sodium-potassium pump then must reestablish the relative ion concentrations across the membrane, necessitating a period in which the cell cannot respond to an excitatory impulse, called the absolute refractory period.

Inhibitory Stimulation

When the message imparted by the neurotransmitter is inhibitory, a different response occurs in the postsynaptic neuron. Instead of depolarizing the membrane by changing the membrane potential from 70 to 55 millivolts, the inhibitory message causes hyperpolarization, raising the difference in charge between the inside and outside of the membrane. The interior of the cell becomes more negative, reaching 80 millivolts or more, thus inhibiting the generation of an action potential in that cell. The inhibitory impulses help prevent the chaos that would result if excitatory impulses were firing with nothing to regulate the chain of stimulation. They also help fine-tune sensory perceptions; they can make sensations more exact and sensitive by blocking the firing of neurons around a specific point, such as the precise place on the skin that a touch is felt.

Role of Neurotransmitters

Transmission of information in the form of electrochemical messages is the job of the entire nervous system. This information movement can be understood through the study of
neurotransmitters. Different parts of the nervous system show the action of many different chemicals that either excite or inhibit the passage of information by means of generation of an action potential in a postsynaptic neuron. The response of the postsynaptic neuron that leads to firing of an action potential is called an excitatory postsynaptic potential (EPSP). If such firing is instead prevented, the response is called an inhibitory postsynaptic potential (IPSP). Together these are referred to as postsynaptic potentials (PSPs).

An important aspect of the generation of these excitatory and inhibitory postsynaptic potentials is that they may be cumulative, with numerous different presynaptic cells sending different messages to the same postsynaptic cell. The messages may all be the same, leading to summation of the information. This would allow a neuron to fire even if each individual excitatory PSP is unable to reach threshold by itself, since the effect can be additive over time (temporal summation, with several messages received from the same cell in a short time) or over space (spatial summation, with several axons sending impulses at the same time). Inhibitory PSPs also have a cumulative effect, but the result of several of these would be to make it harder for the neuron to reach threshold and the development of an action potential. Alternatively, the messages coming into a neuron from several different presynaptic cells might be conflicting, some excitatory and others inhibitory. In this case, the postsynaptic cell would act like a computer and integrate the information from all presynaptic cells to determine whether the net result allows threshold to be reached. If threshold is achieved, the cell fires and a nerve impulse is generated. If threshold is not achieved, the cell does not fire, but it will be brought closer to the action potential by reduction of the voltage difference across the membrane. Since development of an action potential is an all-or-none response, no matter how the threshold is reached the same level of information passage will result. Behavior of an individual organism thus results from the actions of each separate neuron in determining the net balance of incoming information and determining whether an action potential is reached.

Four Types of Neurotransmitters

Neurotransmitters are the chemical messengers that act in the nervous system to excite or inhibit the postsynaptic neurons. At least four neurotransmitters have been studied in detail: acetylcholine, norepinephrine, dopamine, and serotonin. Other transmitter substances have also been examined, such as the amino acids glutamate, aspartate, gamma-aminobutyric acid (GABA), and glucine. From these studies it has been shown that the interpretation of the message lies within the postsynaptic neuron, since the same neurotransmitter may be either inhibitory or excitatory, depending on the tissues in which it is found.

Acetylcholine, for example, is found in both the brain and the peripheral nervous system. Since the peripheral nerves are more accessible to study, more is known about the activities of acetylcholine there than in the brain. Two types of cholinergic receptors (those for acetylcholine) are found in the peripheral nervous system, called muscarinic and nicotinic receptors. Acetylcholine has an excitatory effect on nicotinic receptors, as in causing the contraction of skeletal muscles, but an inhibitory effect on the muscarinic receptors, as in slowing the heartbeat. This neurotransmitter is also believed to cause excitation of tissues in the brain and in autonomic ganglia. In the cerebral cortex, acetylcholine is thought to be involved in cognitive processes, while in the hippocampus it appears to be linked to memory; in the amygdala, it seems to help control emotions.

Norepinephrine, dopamine, and serotonin are monoamines, neurotransmitters that act by means of a second messenger system to produce a postsynaptic response. In this system, cyclic adenosine monophosphate (cAMP) is produced within the cell when a neurotransmitter binds to its receptor, and the cAMP opens the ion channels (a pathway through the cell membrane, controlled by gates and used for passage of ions during electrical impulse generation) that cause excitation or inhibition to be produced. This causes a longer-lasting effect on the postsynaptic neuron, and the neurotransmitters that use this system are apparently involved in long-term behaviors that include memory, emotion, and motivation.

Like acetylcholine, norepinephrine is formed in both the brain and the peripheral nervous tissues, while dopamine and serotonin have been localized to brain tissues only. In the peripheral nervous system, norepinephrine interacts with two kinds of adrenergic receptors on muscle cells, the alpha and beta receptors. Alpha receptors are found on blood-vessel cells, where an excitatory effect results from binding norepinephrine. Beta receptors are seen in the lungs, heart, and intestines, tissues in which norepinephrine has different effects. Binding of the neurotransmitter to beta receptors in cardiac tissue causes excitation, while binding to lung and intestinal receptors inhibits their activities. It is still unclear how the same kind of beta receptor can have different responses in different tissues to the same chemical message. In the brain, a diffuse system of neurons produces norepinephrine, so its effects are widespread, affecting emotion, learning, memory, and wakefulness.

Dopamine is produced by cells found in the substantia nigra, the hypothalamus, and the ventral tegmental areas of the brain, where abnormal levels cause profound behavioral disorders. The related monoamine, serotonin, has distribution and behavioral effects similar to those of norepinephrine. In the upper regions of the brain, the presence of serotonin stimulates higher sensory states and sleep, while reduced levels are associated with severe depression. Since most of the effects of raised or lowered quantities of these mood-altering neurotransmitters seem to cause depression and psychoses, their study has been of great interest. Many of the drugs that have been found to elevate mood clinically act by enhancing or interfering with the action of these neurotransmitters. Through their control of excitation and inhibition of the neural impulse, neurotransmitters control an incredibly complex system of neural interconnections and neuroneffector cell interactions. If this system were under less strict control, behavioral chaos would result, as it does in certain psychiatric and psychological disorders. Applications of knowledge in this area of behavioral research may eventually lead to the ability to control such disorders chemically.

Research on Squid Axons

Studies on the mechanisms of action of the neuron have been ongoing since the 1930s in giant axons of the squid nervous system. Discovered by J. Z. Young, these axons are so large that a single cell can be dissected out and examined in the laboratory. Much of what is known about the human nervous system’s response to excitatory and inhibitory stimuli comes from pioneering work done on these marine mollusks. K. C. Cole and coworkers developed a voltage clamp system of electronic feedback to maintain a constant membrane potential at a chosen voltage level. The axons are penetrated by tiny electrodes and used to measure how electrical transmission occurs in different areas of the neuron across the cell membrane. A later development is the whole cell patch recording, used to examine a small area of the neuron’s cell membrane with ion channels more or less intact. A classic series of papers published by Andrew Huxley and Alan Hodgkin in 1952 explained the regulation of electrical conductance along the neural membrane, including movement of ions across the sodium and potassium channels after excitatory stimulation. Huxley and Hodgkin received a Nobel Prize in 1963 for their work on squid axons.

Effect of Drugs and Transmitter Substances

Another way that excitatory and inhibitory responses are studied is with the muscarinic and nicotinic cholinergic receptors, which are inhibited from working by the actions of the drugs muscarine (from poisonous mushrooms) and nicotine (from tobacco). The drugs mimic the action of acetylcholine on these different kinds of molecules on target tissues. Less is known about the effects of acetylcholine on brain tissues, but this area of research is getting widespread attention because of the evidence that the neurotransmitter appears to be related to the development of Alzheimer’s disease. Acetylcholine deficiency in the nucleus basilis is a general finding at autopsy in patients with this disease of aging, which is accompanied by loss of memory and intellectual ability and by profound personality changes.

Behavioral disturbances, including depression and mania, are also caused by abnormally high or low concentrations of norepinephrine in the brain. Some of the drugs used to treat depression are able to do so by controlling the levels of norepinephrine and thus the stimulation of excitatory and inhibitory pathways in the brain. Dopamine is associated with Parkinson’s disease, in which there is an abnormally low level in the substantia nigra of the brain, and the condition can be treated by increasing the amount of dopamine and by slowing its breakdown in this region. In addition, an abnormally high level of dopamine in other parts of the brain has been associated with causing schizophrenia, suggested by the fact that drugs which block the actions of dopamine also reduce the behavioral aberrations seen in this disease. Since brains of patients with these diseases are studied at autopsy and not during the actions that cause the behaviors, it is difficult to tell what actually occurs at the synapses and whether actions are attributable to inhibition or excitation of particular neurons.

Other transmitter substances include amino acids and neuropeptides, but less information has been gathered on these chemicals, and less is known about their activities in the nervous system and behavior. Glutamate and aspartate are amino acids that are thought to be the main excitatory chemicals in use in the brain, while GABA and glycine are inhibitory. GABA is thought to be the most widespread neurotransmitter in the brain, particularly in functions involving movement. Neuropeptides include endorphins, but the mechanisms by which they act are less well known. It is thought that certain cells are able to produce and release both a neurotransmitter such as dopamine and a neuropeptide, giving the nervous system more versatility and complexity in its decision-making capabilities. Perhaps both excitation and inhibition may be handled by the same cell at different times in its regulation of behavioral activities.

Bibliography

Carlson, Neil R. Physiology of Behavior. 10th ed. Boston: Allyn, 2009. Print.

Heilman, Kenneth M., and Edward Valenstein. Clinical Neuropsychology. 5th ed. New York: Oxford UP, 2012. Print.

Jones, H. Royden, Ted M. Burns, Michael J. Aminoff, and Scott L. Pomeroy. The Netter Collection of Medical Illustrations: Nervous System. 2nd ed. Philadelphia: Saunders, 2013. Print.

Kolb, Bryan, and Ian Q. Whishaw. Fundamentals of Human Neuropsychology. 6th ed. New York: Worth, 2009. Print.

Levitan, Irwin B., and Leonard K. Kaczmarek. The Neuron: Cell and Molecular Biology. 3d ed. New York: Oxford UP, 2002. Print.

López-Muñoz, Francisco, and Cecilio Alamo. "Historical Evolution of the Neurotransmission Concept." Journal of Neural Transmission 116.5 (2009): 515–33. Print.

Ornstein, Robert, and Richard F. Thompson. The Amazing Brain. 1984. Reprint. Boston: Houghton, 1991. Print.

Restak, Richard M. The Mind. Toronto: Bantam, 1988. Print.

Tortora, Gerard J., and Nicholas P. Anagnostakos. Principles of Anatomy and Physiology. New York: Wiley, 2008. Print.