Who is Jack Merridew and what does he look like in Lord of the Flies?

Jack Merridew is the leader of the boys’ choir, and later the hunters, and Ralph’s competitor for leadership on the island.

Jack Merridew is a natural leader.  He actually has leadership experience, unlike Ralph.  He has been the choir leader at his school, and he seems to take responsibility over the choir even after they crash land on the island.  This is because Jack loves power, and he is not willing to give it up just because they are not in school.

Jack takes everything seriously.  He wants control and power.  Even the physical description of him seems to reinforce these characteristics.

Inside the floating cloak he was tall, thin, and bony; and his hair was red beneath the black cap. His face was crumpled and freckled, and ugly without silliness. Out of this face stared two light blue eyes, frustrated now, and turning, or ready to turn, to anger. (Ch. 1) 

Jack is mercurial.  When Ralph is chosen leader, he accepts it more easily than you would think.  This is because he seems to know that he will be able to challenge Ralph eventually. The conch gave Ralph leadership, but Jack’s abilities are innate. 

“The choir belongs to you, of course.”

“They could be the army—”

“Or hunters—”

“They could be—”

The suffusion drained away from Jack’s face. Ralph waved again for silence.

“Jack’s in charge of the choir. They can be—what do you want them to be?”

“Hunters.” (Ch. 1)

As leader of the hunters, Jack is eventually successful in getting meat.  The allure of savagery leads the other boys to join him.  Jack represents the much more attractive aspects of killing and dancing with war paint.  As leader, he does not try to institute democracy and order like Ralph.  His is a dictatorial regime.  He does things like tie kids to trees and have them beaten.

In the end, it is the chaos that Jack causes when he breaks up the group and his propensity to savagery that leads to the deaths of Piggy and Simon.  Ralph knows this, and he blames himself because he could not maintain leadership.  By giving in to Jack, he doomed them all.

What is urethritis?

Causes and Symptoms

Urethritis
is most often contracted through intercourse with a partner infected with a sexually transmitted disease (STD), particularly gonorrhea and chlamydia. It will usually appear a few days after sex. Urethritis may also be caused by a variety of other organisms, including Escherichia coli (E. coli) and Mycoplasma genitalium bacteria, Trichomonas vaginalis
protozoa, and herpes simplex viruses. Another source of the disease is irritation of the urethra produced by soaps, lotions, or spermicides. Trauma produced by medical instruments, such as urinary catheters or cystoscopes, can also generate urethritis. Complicated urethritis may be associated with kidney stones, a weak immune system, or malformations of the urinary tract. There are cases of nonspecific urethritis that have no known cause.

General symptoms for males and females include burning or pain when urinating, unusually frequent urination, and chills or fever. In males, pus and cloudy discharges may come from the penis, and the opening to the penis may stick together from dried-up secretions and may be red, sore, and itchy. In females, vaginal discharge may be present, as well as discomfort in the rectal area and pain or bleeding during sexual intercourse. In some cases, no accompanying symptoms are associated with urethritis.

Treatment and Therapy

To assess possible bacterial sources of urethritis, urinalysis and urine culture laboratory tests are performed. Abnormal genital discharges and, in some cases, urethral swabs are also examined. If urethritis is diagnosed, then antibiotics are usually administered. The most common ones used are doxycycline, azithromycin, erythromycin, roxithromycin, and tetracycline. Even for cases of nonspecific urethritis, antibiotics have provided an effective treatment. Drinking copious fluids can help dilute bacteria and flush the urinary system. Acupuncture and homeopathic therapies sometimes help relieve the effects of urethritis.

If symptoms of urethritis are present, then the urethra should be rested by abstaining from sexual intercourse and masturbation until medical treatment has been received. When treated quickly and correctly, the symptoms are usually resolved in one to two weeks. Without proper treatment, serious complications might include infection spreading into the bladder or kidneys, as well as transmission of the causative organism to a sexual partner.

When it is not associated with a general urinary tract infection, urethritis is more common in males than females, probably because males have a longer urethra. In some individuals, nonspecific urethritis can have a high recurrence rate. Burning during urination can be reduced by adding a small amount of baking soda to drinking water to reduce the acidity of urine. Cranberry juice contains a compound that prevents bacteria from sticking to the urethra and growing there.

Bibliography

Beers, Mark H., et al., eds. The Merck Manual of Diagnosis and Therapy. 18th ed. Whitehouse Station, N.J.: Merck Research Laboratories, 2006.

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

Schmitt, Barton D. Your Child’s Health: The Parents’ One-Stop Reference Guide to Symptoms, Emergencies, Common Illnesses, Behavior Problems, Healthy Development. Rev. ed. New York: Bantam Books, 2005.

What is chickenpox?

Causes and Symptoms

Chickenpox is an acute, highly infectious
viral disease occurring primarily, but not exclusively, in children. Each year, between three and four million cases are reported in the United States, with the highest incidence occurring during the late winter and early spring. About ten to thirteen thousand of those affected became so ill that they require hospitalization; since the introduction of the varicella-zoster virus vaccine, the number of cases and the number of hospitalizations have dropped significantly.

The varicella-zoster virus (VZV) is responsible for chickenpox infection. Physical contact with an infected individual is not required, as the virus is transmitted from person to person via an airborne route.

Symptoms begin to appear about eleven to fifteen days after exposure. At first, they may resemble those of the common cold: sore throat, runny nose, malaise, and fever. Soon, red spots appear on the body, usually beginning on the trunk and scalp and spreading outward. Occasionally, the mucous membranes are affected as well, with spots appearing in the mouth and nasal passages. The spots develop into vesicles—raised bumps with clear, teardrop-shaped blisters that turn rapidly to crusty lesions within six to eight hours. The rash occurs in waves, with new spots developing as old ones heal and disappear. By the fifth or sixth day, no new lesions will develop, and the crusts will be gone in less than twenty days.

Chickenpox causes intense itchiness. The impulse to scratch can be overwhelming and can lead to one of the most common complications: bacterial skin infections. Scratching the lesions can also lead to ugly pox scarring. Other possible complications of chickenpox include viral pneumonia and viral encephalitis.

The diagnosis of chickenpox is almost always done on the basis of its symptoms, most notably its characteristic rash accompanied by fever. In the event that confirmation of the disease is necessary, the fluid in the lesions can be cultured, although by the time results are obtained (five to ten days), the disease is usually on its way to resolution.

Treatment and Therapy

In children, chickenpox, uncomfortable although it may be, is not considered a serious illness. The vast majority of cases are uncomplicated and resolve themselves within two to three weeks. Treatment is therefore primarily symptomatic, with an emphasis on controlling itching and reducing fever.

Oral antihistamines
such as Benadryl (diphenhydramine) and Atarax (hydroxyzine) are effective in managing pruritus. Topical treatments, such as calamine lotion, and wet compresses may offer almost immediate relief. Fever is treated with acetaminophen. Aspirin is not an option because of its link to Reye’s syndrome, a potentially fatal condition characterized by vomiting, disorientation, and eventual coma. Ibuprofen should also be avoided, as it may be linked to secondary infections.

Some parents trim short the fingernails of infected children to keep them from scratching away the crusts of chickenpox lesions. This is one way of reducing the risk of secondary bacterial infections. Frequent bathing is also helpful in preventing this complication.

Although there is no cure for chickenpox, the oral antiviral drugs acyclovir, valacyclovir, and famciclovir have been shown to be effective in decreasing the intensity of itching, hastening the healing of skin lesions, and generally shortening the duration of the disease. To be effective, treatment must begin within twenty-four hours of the appearance of the rash.

The use of acyclovir is not recommended for most children because of the relatively benign nature of the disease in this age group. However, for some high-risk children, such as premature infants, therapy should be started within twenty-four hours of the onset of illness. In adolescents older than age thirteen, adults, and immunocompromised individuals, however, chickenpox may have severe complications, and this increased risk may be lessened with acyclovir therapy.

Affected newborns and immunocompromised persons may receive gammaglobulin intravenously or oral acyclovir immediately following exposure to the virus.

Perspective and Prospects

Chickenpox has been around for so long that there are conflicting accounts about how it got its name. One theory has it that when chickenpox was first described, it was noted that its lesions looked as if they were placed upon the skin rather than arising from the skin itself. They were compared to chickpeas—hence the name. Another idea is that the term “chickenpox” was intended to distinguish this weaker pox illness from the more life-threatening smallpox—the term “chicken” being used, as in “chickenhearted,” to mean weak or timid.

Chickenpox was not considered a distinct rash disease until 1553, when the Italian physician Filippo Ingrassia differentiated it from scarlet fever. In 1785, the English physician William Heberden gave the earliest clear description of varicella, having distinguished it from smallpox in 1768. In 1924, T. M. Rivers and W. S. Tillett reported the isolation of the chickenpox virus.

Throughout history, the treatment of chickenpox has been symptomatic. In the 1970s, however, a vaccine became available for persons in high-risk categories. In 1995, a vaccine called Varivax was approved by the US Federal Food and Drug Administration for use in children over the age of one; other brands of the vaccine are available in Canada, the United Kingdom, and Australia. Varivax is 70 to 90 percent effective in preventing chickenpox over the short term. Vaccinated individuals who still develop chickenpox get a milder form of the disease. Immunity from the vaccine may wane over time, so booster shots may be needed. The vaccine’s ability to provide long-term protection from chickenpox is still unknown.

Bibliography

A.D.A.M. Medical Encyclopedia. "Chickenpox." MedlinePlus, August 2, 2011.

Alan, Rick, and Michael Woods. "Chickenpox (Varicella)." Health Library, October 11, 2012.

Behrman, Richard E., et al. Nelson Textbook of Pediatrics. 19th ed. Philadelphia: Saunders/Elsevier, 2011.

Kiple, Kenneth F., ed. The Cambridge World History of Human Disease. New York: Cambridge University Press, 2008.

Kump, Theresa. “Chicken-Pox Survival Guide.” Parents 69, no. 5 (May, 1994): 29–31.

Marquis, Julie. “Chickenpox Vaccine Is Swaying Skeptics.” Los Angeles Times, June 21, 2000, p. 1.

National Center for Immunization and Respiratory Diseases, Division of Viral Diseases. "Monitoring the Impact of Varicella Vaccination."Centers for Disease Control and Prevention, August 30, 2012.

Sadovsky, Richard. “Safety and Effectiveness of Varicella Vaccine.” American Family Physician 61, no. 7 (April 1, 2000): 2209.

“Varicella (Chickenpox).” In Conn’s Current Therapy, edited by Rick D. Kellerman et al. Philadelphia: Saunders/Elsevier, 2012.

Whitley, Richard J. “Varicella-Zoster Virus.” In Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, edited by Gerald L. Mandell, John F. Bennett, and Raphael Dolin. 7th ed. New York: Churchill Livingstone/Elsevier, 2010.

What affects ionization energy?

Ionization energy is the energy needed to remove one or more electrons from a neutral atom. For instance, there is a corresponding ionization energy needed to produce Na+ from the neutral Na (sodium) atom. The energy is used to 'take away' the electron, which is stably revolving around the nucleus of the atom.

In the periodic table, there is a very noticeable trend in ionization energy. It increases as you go from left to right, and decreases as you go from top to bottom. Hence, Fluorine has a higher ionization energy than Lithium, and Oxygen has a higher ionization energy than Selenium. You might have noticed that in chemical reactions, particularly the formation of ions, fluorine usually gets a negative charge (F-) while lithium a positive charge (Li+). This is because atoms with lower ionization energies tend to have positive charges (easier to remove electrons) and those with higher IE tend to produce anions (harder to remove electrons, but easier to add another one to complete the octet as in the case of F-). This trend can be explained by various factors and related trends:

1. Size of the atom- Electrons are attracted to the nucleus. The stronger the attraction, the harder it is to get them to be released. As the atom size increases, the electron moves farther from the nucleus, and hence is easier to remove. The larger Selenium atom has a lower ionization energy than the smaller oxygen atom.


2. Nuclear charge- Higher nuclear charge atoms attract electrons more strongly, and have higher ionization energies as a result. In the same row, atoms to the right have higher nuclear charge (more protons). Hence, fluorine has a higher ionization energy than lithium.


3. Shielding effect- This is related to the actual attractive force 'felt' by the valence shell electrons. The higher the number of inner shells, the lower this gets and the lower the ionization energy. Atoms towards the bottom of the periodic table have more inner shells, and hence are lower in ionization energy.

These main factors affect ionization energy and also affect each other. The key thing to remember is ionization energy is dependent on how strongly the electrons are attracted to an atom's nucleus.

optimization models in transportation engineering

Transport Engineering is applying science and technology in designing, planning, operating and managing the facilities of any type of transport to provide safe, efficient. rapid. comfortable and economical transportation. In order to do this we need Mathematical optimization models. 

A combined model used by Watdrop and Dafermos & Sparrow was used to find an optimization model for Transport Engineering. 

Watdrop models is based on two principles: 

1st principle:

The journey times of all routes are equal, and is less than those that would be experience by one vehicle or any unused route.

2nd principle:

The average time of the journey is at its minimum. 

Defermos & Sparrow model is based on two distinct behavior and principles: 

1. User Optimization Equilibrium Principle:

The cost of the person using the transport network on the used paths for each origin/destination are equal and at the minimum.

2. System Optimization Principle: 

The marginal total cost for travel used on the paths used for each origin/destination are equal and a minimum.

The combination of these two principles are used to design an optimization model for Transport Engineering. For more detailed information on this model, follow the link below.

In a solution of sugar and water, what is the solute and what is the solvent?

A solute is a substance that is "dissolved into" the solvent, while the solvent is the substance "into which" something is dissolved. Now, when we prepare sugar water, we mix sugar into water and thus sugar is the solute, while water is the solvent. The solvent is generally the bulk phase, which is water in this case. Thus, for sugar water:

solute: sugar

solvent: water

Similarly, when we mix salt into the water to make some brine solution, salt is the solute, while water is the solvent.

While preparing solutions, we can alter the rate of the dissolution of solutes by increasing their surface area (using crushed sugar instead of sugar cubes) and by stirring the solution. We can also increase the solubility of a particular solute into solvent by increasing the temperature of the solvent.

Hope this helps. 

What is cloning?

Types of Cloning

There are three different definitions of a clone. One is a group of genetically identical cells descended from a single common ancestor. This type of clone is often made by plant cell tissue culture in which a whole line of cells is made from a single cell ancestor. A second type of clone is a gene clone, or recombinant DNA clone, in which copies of a DNA sequence are made by genetic engineering. A third type of clone is an organism that is descended asexually from a single ancestor. A much-celebrated example of an organismal clone is the sheep Dolly (1997-2003), produced by placing the nucleus of a cell from a ewe’s udder, with its genetic material (DNA), into an unfertilized egg from which the nucleus had been removed.

DNA Cloning

DNA is cloned to obtain specific pieces of DNA that are free from other DNA fragments. Clones of specific pieces of DNA are important for basic research. DNA is made up of four different compounds known as nucleotide bases. Once a piece of DNA is cloned, the specific DNA bases can be identified. This is called sequencing. Once this specific pattern of DNA sequencing is accomplished, the DNA is said to be “sequenced,” revealing the genetic code detailed by the nucleotide bases. This valuable information helps answer the following questions and can be used in a variety of ways. Where does the gene begin and end? What type of control regions does the gene have? Cloned DNAs can be used as hybridization probes, where sequences that are complementary to the cloned DNA can be detected. Such DNA hybridization is useful to detect similarities between genes from different organisms, to detect the presence of specific disease genes, and to determine in what tissues that gene is expressed. The gene is expressed when a messenger RNA (mRNA) is made from the gene and the mRNA is translated into a protein product. A DNA clone is also used to produce the protein product for which that gene codes. When a clone is expressed, the protein made by that gene can be studied or an antibody against that protein can be made. An antibody is used to show in which tissues of an organism that protein is found. Also, a DNA clone may be expressed because the gene codes for a useful product. This is a way to obtain large amounts of the specific protein.

Products of Recombinant DNA Technology

Recombinant DNA technology has produced clones put to use for a wide variety of human purposes. For example, rennin and chymosin are used in cheese making. One of the most important applications, however, is in medicine. Numerous recombinant DNA products are useful in treating human diseases, including the production of human insulin (Humalin) for diabetics. Other human pharmaceuticals produced by gene cloning include clotting factor VIII to treat hemophilia A, clotting factor IX to treat hemophilia B, human growth hormone, erythropoietin to treat certain anemias, interferon
to treat certain cancers and hepatitis, tissue plasminogen activator to dissolve blood clots after a heart attack or stroke, prolastin to treat genetic emphysemas, thrombate III to correct a genetic antithrombin III deficiency, and parathyroid hormone. The advantages of the cloned products are their high purity, greater consistency from batch to batch, and the steady supply they offer.

How to Clone DNA

DNA is cloned by first isolating it from its organism. Vector DNA must also be isolated from bacteria. (A vector is a plasmid or virus into which DNA is inserted.) Both the DNA to be cloned and the vector DNA are cut with a restriction enzyme that makes sequence-specific cuts in the DNAs. The ends of DNA molecules cut with restriction enzymes are then joined together with an enzyme called ligase. In this way the DNA to be cloned is inserted into the vector. These recombinant DNA molecules (vector plus random pieces of the DNA to be cloned) are then introduced into a host, such as bacteria or yeast, where the vector can replicate. The recombinant molecules are analyzed to find the ones that contain the cloned DNA of interest.

Regulation of DNA Cloning

In the 1970s the tools to permit cloning of specific pieces of DNA were developed. There was great concern among scientists about the potential hazards of some combinations of DNA from different sources. Concerns included creating new bacterial plasmids with new drug resistances and putting DNA from cancer-causing viruses into plasmids. In February, 1975, scientists met at a conference center in Asilomar, California, to discuss the need to regulate recombinant DNA research. The result of this conference was the formation of the Recombinant DNA Molecule Program Advisory Committee at the National Institutes of Health, and guidelines for recombinant DNA work were established.

Genetically Modified Organisms

Numerous cloned genes have been introduced into different organisms to produce genetically modified organisms (GMOs). Genes for resistance to herbicides and insects have been introduced into soybean, corn, cotton, and canola, and these genetically engineered plants are in cultivation in fields in the United States and other countries. Fish and fruit and nut trees that mature more rapidly have been created by genetic engineering. Edible vaccines have been made—for example, a vaccine for hepatitis B in bananas. A tomato called the Flavr Savr is genetically engineered to delay softening. Plants that aid in bioremediation by taking up heavy metals such as cadmium and lead are possible.

Concerns about genetically modified organisms include safety issues—for example, concerns that foreign genes introduced into food plants may contain allergens and that the antibiotic resistance markers used in creating the GMOs might be transferred to other organisms. There are concerns about the environmental impact of GMOs; for example, if these foreign genes are transferred to other plants by unintended crossing of a GMO with a weed plant, weeds may become difficult or impossible to eradicate and jeopardize crop growth. There is a concern about the use of genetically modified organisms as food. There is a concern about loss of biodiversity if only one, genetically modified, variety of a crop plant is cultivated. There are also ethical concerns surrounding whether certain GMOs might be made available only in rich countries, and there are concerns about careful labeling of GMOs so that consumers will be aware when they are using products from GMOs. All of these questions remain in flux as the marketing of GMOs proceeds.

According to the International Service for the Acquisition of Agri-Biotech Applications (ISAAA), genetically modified (GM) crops were planted in twenty-seven countries by approximately 18 million farmers worldwide. Over 60 percent of the world's population live in the twenty-seven countries that are planting GM crops. In 2006, US government statistics showed that 87 percent of the global genetically modified crops were grown in developed countries. By 2013, however, ISAAA reported that Latin American, Asian, and African farmers grew 54 percent of the global GM crops compared to the 46 percent grown in developed countries worldwide. Corn, soybeans, cotton, alfalfa, and canola were the major crops, often modified for insect resistance. Rice has been genetically enhanced for more iron and vitamins to alleviate malnutrition in Asia. Other plants have been modified to survive weather variances.

Genetically modified organisms may soon include cows resistant to mad cow disease and nut and fruit trees that yield bounties faster. Plants producing new plastics and fish that grow faster are potential genetically modified organisms. It is expected that the world will see huge increases in genetically modified organisms as researchers gain more access to genomic resources.

Organismal Cloning

A goal of organismal cloning is to develop ways of efficiently altering animals genetically in order to reproduce certain animals that are economically valuable. Animals have been altered by the introduction of specific genes, such as human proteins that will create drug-producing animals. Some genes have been inactivated in organisms to create animal models of human diseases. For example, “knockout mice” are used as models for diabetes research. Another goal is to conduct research that might lead to the development of human organs for transplant produced from single cells. Similarly, animals might be genetically engineered to make their organs better suited for transplantation to humans. Finally, the cloning of a human might be a solution to human infertility.

Are Organismal Clones Normal?

There is, however, a concern about the health of cloned animals. First of all, when inserting a new nucleus into an egg from which the nucleus has been removed, and then implanting such eggs into surrogate mothers, only very few of the eggs develop properly. There are suggestions of other abnormalities in cloned animals that might be due to the cloning process. The first vertebrate to be successfully cloned, the sheep Dolly, developed first arthritis and then a lung disease when six years old; although neither condition was unusual in sheep, both appeared years earlier than normal, and Dolly was euthanized. Was she genetically older than her chronological age?

Stem Cells

Stem cells are unspecialized cells that are able to divide continuously and, with the proper conditions, be induced to give rise to specialized cell types. In the developing embryo they give rise to the hundreds of types of specialized cells that make up the adult body. Embryonic stem cells can be isolated from three- to five-day-old embryos. Some tissues in the adult, such as bone marrow, brain, and muscle, contain adult stem cells that can give rise to cell types of the tissue in which they reside.

A goal of research on stem cells is to learn how stem cells become specialized cells. Human stem cells could be used to generate tissues or organs for transplantation and to generate specific cells to replace those damaged as a result of spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, rheumatoid arthritis, and other conditions.

A 2012 study demonstrated that human corneas can be cultivated from stem cells and grown onto the damaged corneas of individuals who are at risk for blindness. This new technology does away with the need for cornea donors. Prior to this discovery, corneas could only be replaced by a donated cornea, which historically had been in short supply. (The cornea is the outermost portion of the eye and provides protection along with 70 percent of the eye’s focusing power.)

Regulation of Organismal Cloning

Until the cloning of the sheep Dolly in 1997, it was thought that adult specialized cells could not be made to revert to nonspecialized cells that can give rise to any type of cell. However, Dolly was created from a specialized adult cell from a ewe’s udder. After the publicity about Dolly, US president Bill Clinton asked the National Bioethics Advisory Commission to form recommendations about the ethical, religious, and legal implications of human cloning. In June, 1997, that commission concluded that attempts to clone humans are “morally unacceptable” for safety and ethical reasons. There was a moratorium on using federal funds for human cloning. In January, 1998, the US Food and Drug Administration (FDA) declared that it had the authority to regulate human cloning and that any human cloning must have FDA approval.

While there is general agreement in the United States and in many other countries that reproductive human cloning should be banned because of ethical and safety concerns, there is ongoing debate about whether or not to allow therapeutic cloning to treat human disease or research cloning to study how stem cells develop. The Human Cloning Prohibition Act of 2001 to ban both reproductive and therapeutic cloning passed in the US House of Representatives, but the Senate did not support the ban. The ban was again considered by the lawmakers in 2002. In the meantime, individual states such as California and New Jersey have passed bills that approve of embryonic stem cell research with the goal of leading to treatments for diseases such as Parkinson’s, diabetes, and Alzheimer’s. The research is controversial because embryos must be destroyed to obtain the stem cells, and some groups believe that constitutes taking a human life. The embryos used are generally extra embryos left over from in vitro fertilizations. In December 2002 and January 2003, a company called Clonaid announced the births of several babies it claimed were the result of human cloning but then failed to produce any scientific evidence that the babies were clones. In February, 2003, the US Congress considered a ban on both reproductive and therapeutic cloning. In late February, the House passed the Human Prohibition Cloning Act of 2003, banning the cloning of human beings but allowing limited research on some existing stem cell lines.

In May, 2008, President George W. Bush signed into law the Genetic Information Nondiscrimination Act (GINA). GINA prohibits US employers and insurance companies from discriminating on the basis of genetic test information, and insurance companies may not discriminate with reduced coverage or increased pricing based on information derived from genetic testing. Employers are prohibited from making adverse employment decisions based on an individual’s genetic code. Under GINA law, insurers and employers may not demand or request a genetic test.

GINA protections are meant to encourage increased genetic testing without the fear of job loss or insurance complications. It is hoped that more genetic testing will enable researchers to devise therapies for a wide range of hereditary diseases. Genetic testing may also enable earlier treatments with better outcomes and decreased health care costs.

Executive order 13505, “Removing Barriers to Responsible Scientific Research Involving Human Stem Cells,” was issued by President Barack Obama in March, 2009. This executive order requires the Health and Human Services secretary and the National Institutes of Health (NIH) director to review and issue new NIH guidelines regarding scientific research and human stem cells.

The tension between scientific possibility, public policy, and societal values continues in the arena of cloning. Through therapeutic cloning there is great potential for the treatment of human diseases, but the ethical concerns about such procedures must be carefully considered as well.

Key terms



cloning vector

:

a plasmid or virus into which foreign DNA can be inserted to amplify the number of copies of the foreign DNA in the host cell or organism





DNA


:

dexoyribonucleic acid, a long-chain macromolecule, made of units called nucleotides and structured as a double helix joined by weak hydrogen bonds, that forms genetic material for most organisms




DNA hybridization

:

formation of a double-stranded nucleic acid molecule from single-stranded nucleic acid molecules that have complementary base sequences




ligase

:

an enzyme that joins recombinant DNA molecules together




plasmid

:

a DNA molecule that replicates independently of chromosomes





recombinant DNA technology


:

methods used to splice a DNA fragment from one organism into DNA from another organism and then clone the new recombinant DNA molecule




reproductive cloning

:

cloning to produce individual organisms




restriction enzyme

:

a protein (an enzyme) that recognizes a specific nucleotide sequence in a piece of DNA and causes a sequence-specific cleavage of the DNA





stem cells


:

cells that are able to divide indefinitely in culture and to give rise to specialized cells




therapeutic cloning

:

cloning to produce a treatment for a disease





Bibliography

Boylan, Michael. “Genetic Engineering.” In Medical Ethics, edited by Boylan. Upper Saddle River, N.J.: Prentice Hall, 2000. Print.

Cibelli, Jose B., Robert P. Lanza, Michael D. West, and Carol Ezzell. “The First Human Cloned Embryo.” Scientific American 286, no. 1 (2002): 44–48. Print.

Espejo, Roman, ed. Biomedical Ethics: Opposing Viewpoints. San Diego: Greenhaven Press, 2003. Print.

Fredrickson, Donald S. The Recombinant DNA Controversy, a Memoir: Science, Politics, and the Public Interest, 1974–1981. Washington, D.C.: ASM Press, 2001. Print.

Hanson, Charles, et al. "Transplantation of Human Embryonic Stem cells onto a Partially Wounded Human Cornea In Vitro." Acta Ophthalmologica 91.2 (Mar 2013): 127–30. Print.

"ISAAA Brief 46-2013: Executive Summary." ISAAA. ISAAA, 25 Mar. 2014. Web. 28 July 2014.

Jensen, Eric A. The Therapeutic Cloning Debate: Global Science and Journalism in the Public Sphere. Surrey: Ashgate, 2014. Print.

Klotzko, Arlene Judith, ed. The Cloning Sourcebook. New York: Oxford University Press, 2001. Print.

Kreuzer, Helen, and Adrianne Massey. Recombinant DNA and Biotechnology: A Guide for Teachers. Washington, D.C.: ASM Press, 2001. Print.

Lauritzen, Paul, ed. Cloning and the Future of Human Embryo Research. New York: Oxford University Press, 2001. Print.

Lavi, Shai. "Cloning International Law: The Science and Science Fiction of Human Cloning and Stem-Cell Patenting." Law, Culture, and the Humanities. Assn. for the Study of Law, Culture, and the Humanities, 13 Mar. 2014. Web. 28 July 2014.

Lynch, Colum. "UN Backs Human Cloning Ban." Washington Post. Washington Post, 9 Mar. 2005. Web. 28 July 2014.

Prado, José Rafael, et al. "Genetically Engineered Crops: From Idea to Product." Annual Review of Plant Biology 65 (Apr. 2014): 769–90. Print.

Schatten, G., R. Prather, and I. Wilmut. “Cloning Claim Is Science Fiction, Not Science.” Science 299 (2003): 344. Print.

Semple, Kirk. "UN to Consider Whether to Ban Cloning of Human Embryos." New York Times. New York Times, 3 Nov. 2003. Web. 28 July 2014.

What is the special appointment in "After Twenty Years"?

The "special appointment" is fully explained by Bob when the uniformed patrolman whom he doesn't recognize as his old friend Jimmy Wells stops in front of him at the doorway of the closed hardware store.

“Twenty years ago tonight,” said the man, “I dined here at ‘Big Joe’ Brady's with Jimmy Wells, my best chum, and the finest chap in the world. He and I were raised here in New York, just like two brothers, together. I was eighteen and Jimmy was twenty. The next morning I was to start for the West to make my fortune. You couldn't have dragged Jimmy out of New York; he thought it was the only place on earth. Well,we agreed that night that we would meet here again exactly twenty years from that date and time, no matter what our conditions might be or from what distance we might have to come. We figured that in twenty years each of us ought to have our destiny worked out and our fortunes made, whatever they were going to be.”

Bob expected to meet his old friend in front of a big, busy restaurant. He doesn't like having to stand in front of a closed hardware store because he knows he is conspicuous. But the restaurant was torn down five years ago and replaced by some shops. Bob has no choice but to wait on that spot because that is the only place Jimmy would know where to look for him.

O. Henry invented the "special appointment" because it was a good way to bring two old friends together in the great city of New York after they haven't seen each other in twenty years. The author didn't want the two men meeting at a big, crowded, well-lighted restaurant, because Bob would not feel nervous and compelled to explain what he was doing there. In other words, it would not look suspicious to be meeting a man at a restaurant, but it does look suspicious for a man to be standing "In the doorway of a darkened hardware store."

The "special appointment" leads to Bob being in this dark doorway in this darkened neighborhood. This leads to Bob's nervousness and confusion when the cop stops right in front of him, and this leads to Bob's providing all the necessary exposition to the reader in the form of dialogue to the cop. Jimmy doesn't introduce himself immediately because the doorway is dark and he hasn't seen his old friend in twenty years. "After Twenty Years" is a story in which O. Henry wanted to be totally objective and not explain anything to the reader in the form of prose exposition by a anonymous omniscient narrator. 

What is exercise physiology?

Science and Profession

The primary aim of research in the field of exercise physiology is to gain a better understanding of the quantity and type of exercise needed for health maintenance and rehabilitation. A major goal of professionals in exercise physiology is to find ways to incorporate appropriate levels of physical activity into the lifestyles of all individuals.

Physiology is the science of the physical and chemical factors and processes involved in the functioning of living organisms. Exercise physiology examines these factors and processes as they relate to physical exertion. The physical responses that occur are specific to the intensity, duration, and type of exercise performed.

Exercise of low or moderate intensity relies on oxygen to release energy for work. This process is often referred to as aerobic exercise. In the muscles, carbohydrates and fats are broken down to produce adenosine triphosphate (ATP), the basic molecule used for energy. Aerobic exercise can be sustained for several minutes to several hours.

Higher-intensity exercise is predominantly fueled anaerobically (in the absence of oxygen) and can be sustained for up to two minutes only. Muscle glycogen is broken down without oxygen to produce ATP. Anaerobic metabolism is much less efficient at producing ATP than is aerobic metabolism.

During anaerobic metabolism, a by-product called lactic acid begins to accumulate in the blood as blood lactate. The point at which this accumulation begins is called the anaerobic threshold (AT), or the onset of blood lactate accumulation (OBLA). Blood lactate can cause muscle soreness and stiffness, but it also can be used as fuel during aerobic metabolism.

A third and less often used energy system is the creatine phosphate (ATP-CP) system. Using the very limited supply of ATP that is stored in the muscles, phosphate molecules are exchanged between ATP and CP to provide energy. This system provides only enough fuel for a few seconds of maximum effort.

The type of muscle fiber recruited to perform a specific type of exercise is also dependent on exercise intensity. Skeletal muscle is composed of “slow-twitch” and two types of “fast-twitch” muscle fibers. Slow-twitch fibers are more suited to using oxygen than are fast-twitch fibers, and they are recruited primarily for aerobic exercise. One type of fast-twitch fiber also functions during aerobic activity. The second type of fast-twitch fiber serves to facilitate anaerobic high-intensity exercise.

Exercise mode is another factor in people's physiological responses to exercise. Dynamic exercise (alternating muscular contraction and relaxation through a range of motion) using many large muscles requires more oxygen than does activity using smaller and fewer muscles. The greater the oxygen requirement of the physical activity, the greater the cardiorespiratory benefits.

Many bodily adaptations occur over a training period of six to eight weeks, and other benefits are gradually manifested over several months. The positive adaptations include reduced resting and working heart rates. As the heart becomes stronger, there is a subsequent increase in stroke volume (the volume of blood the heart pumps with each beat), which allows the heart to beat less frequently while maintaining the same cardiac output (the volume of blood pumped from the heart each minute). Another beneficial adaptation is increased metabolic efficiency. This is partially facilitated by an increase in the number of mitochondria (the organelles responsible for ATP production) in the muscle cells.

One of the most recognized representations of aerobic fitness is the maximum volume of oxygen (VO2max) an individual can use during exercise. VO2max is improved through habitual, relatively high-intensity aerobic activity. After three to six months of regular training, levels of high-density lipoproteins (HDLs) in the blood increase. HDL molecules remove cholesterol, a fatty substance, from the tissues to aid in protecting the heart from atherosclerosis.

Various internal and external factors influence the metabolic processes that take place during and after exercise. Internally, nutrition, degree of hydration, body composition, flexibility, sex, and age are some of the variables that play a role in the physiological responses. Other internal variables include medical conditions such as heart disease, diabetes, and hypertension (high blood pressure). Externally, environmental conditions such as temperature, humidity, and altitude alter how the exercising body functions.

Various modes of exercise testing and data collection are used to study the physiological responses of the body to exercise. Treadmills and cycle ergometers (instruments that measure work and power output) are among the most common methods of evaluating maximum oxygen consumption. During these tests, special equipment and computers analyze expired air, heart rate is monitored with an electrocardiograph (ECG), and blood pressure is taken using a sphygmomanometer. Blood and muscle-fiber samples can also be extracted to aid in identifying the fuel system and type of muscle fibers being used. Other data sometimes collected, such as skin temperature and body-core temperature, can provide pertinent information.

Metabolic equivalent units, or METs, are often used to translate a person’s capability into workloads on various pieces of exercise equipment or into everyday tasks. For every 3.5 milliliters of oxygen consumed per kilogram of body weight per minute, the subject is said to be performing at a workload of one MET. One MET is approximately equivalent to 1.5 kilocalories per minute, or the amount of energy expended per kilogram of body weight in one minute when a person is at rest.

Another factor greatly affecting the physical response to exercise is body composition. The three major structural components of the body are muscle, bone, and fat. Body composition can be evaluated using a combination of anthropometric measurements. These measurements include body weight, standard height, measurements of circumferences at various locations using a tape measure, measurements of skeletal diameters using a sliding metric stick, and measurements of skinfold thicknesses using calipers.

Body fat can be estimated using several methods, the most accurate of which is based on a calculation of body density. This method, called hydrostatic weighing, involves weighing the subject under water while taking into account the residual volume of air in the lungs. The principle underlying this measurement of body density is based on the fact that fat is less dense than water and thus will float, whereas bone and muscle, which are denser than water, will sink. One biochemical technique often used to determine levels of body fat is based on the relatively constant level of potassium-40 naturally existing in lean body mass. Another method uses ultrasound waves to measure the thickness of fat layers. X-rays and computed tomography (CT) scanning can be used to provide images from which fat and bone can be measured. Bioelectrical impedance (BIA) is a method of estimating body composition based on the resistance imposed on a low-voltage electrical current sent through the body. The most widely used and easily assessable method, however, involves measurement of skinfolds at various sites on the body using calipers. In all cases, mathematical formulas have been devised to interpret the collected data and provide the best estimate of an individual’s body composition.

Other tests have been developed to determine muscular strength, muscular endurance, and flexibility. Muscular strength is often measured by performance of one maximal effort produced by a selected muscle group. Muscular endurance of a muscle or muscle group is often demonstrated by the length of time or number of repetitions a particular submaximal workload or skill can be performed.

Two major types of flexibility have been identified. One type consists of the ability to move a muscle group or joint through its full range of motion at low speeds or hold a part of the body still at the extent of its range of motion. This is called static flexibility, and it can be measured using a metric stick or a protractor-type instrument called a goniometer. Dynamic flexibility, the other major identified type of flexibility, is the flexibility through the full range of motion of a muscle group or joint at normal or high speeds. Measuring dynamic flexibility is much more difficult.

Overlapping the science of exercise physiology are the studies of biomechanics or kinesiology (sciences dealing with human movement) and nutrition. Only through an understanding of efficient body mechanics and proper nutrition can the physiological responses of the body to exercise be identified correctly.

Diagnostic and Treatment Techniques

Exercise prescription is the primary focus in the application of exercise physiology. General health maintenance, cardiac rehabilitation, and competitive athletics are three major areas of exercise prescription.

Before making recommendations for an exercise program, an exercise physiologist must evaluate the physical limitations of the exerciser. In a normal health-maintenance setting, often called a “wellness” program, a health-related questionnaire can reveal relevant information. Such a questionnaire should include questions about family medical history and the subject’s history of heart trouble or chest pain, bone or joint problems, and high blood pressure. The presence of any of these problems suggests the need for a physician’s consent prior to exercising. After the individual has been deemed eligible to participate, an assessment of the level of physical fitness should be performed. Determining or estimating VO2max, muscular strength, muscular endurance, flexibility, and body composition is usually part of this assessment. It is then possible to design a program best suited to the needs of the individual.

For the healthy adult participant, the American College of Sports Medicine (ACSM), a widely recognized authoritative body on exercise prescription, recommends three to five sessions of aerobic exercise weekly. Each session should include a five- to ten-minute warm-up period, twenty to sixty minutes of aerobic exercise at a predetermined exercise intensity, and a five- to ten-minute cool-down period.

To recommend an appropriate aerobic exercise intensity, the exercise physiologist must determine an individual’s maximum heart rate. The best way to obtain this maximum heart rate is to administer a maximal exercise test. Such a test can be supervised by an exercise physiologist or an exercise-test technician; it is advisable, especially for the older participant, that a cardiologist also be in attendance. An ECG is monitored for irregularities as the subject walks, runs, cycles, or performs some dynamic exercise to exhaustion or until the onset of irregular symptoms or discomfort.

Exercise prescription using heart rate as a measure can be achieved by various methods. A direct correlation exists between exercise intensity, in terms of oxygen consumption, and heart rate. From data collected during a maximal exercise test, a target heart-rate range of 40 to 85 percent of functional capacity can be calculated. Another method used to determine an appropriate heart-rate range is based on the difference between an individual’s resting heart rate and his or her maximum heart rate, called the heart-rate reserve (HRR). Values representing 60 percent and 80 percent of the HRR are calculated and added to the resting heart rate, yielding the individual’s target heart-rate range. A third method involves calculating 70 percent and 85 percent of the maximum heart rate. Although this method is less accurate than the other two methods, it is the simplest way to estimate a target heart-rate range.

Intensity of exercise can also be prescribed using METs. This method relies on the predetermined metabolic equivalents required to perform activities at various intensities. Activity levels reflecting 40 to 85 percent of functional capacity can be calculated.

The rating of perceived exertion (RPE) is another method of prescribing exercise intensity. Verbal responses by the participant describing how an exercise feels at various intensities are assigned to a numerical scale, which is then correlated to heart rate. Through practice, the participant learns to associate heart rate with the RPE, reducing the necessity of frequent pulse monitoring in the healthy individual.

Adequate physical fitness can be defined as the ability to perform daily tasks with enough reserve for emergency situations. All aspects of health-related fitness direct attention toward this goal. Aerobic exercise often provides some conditioning for muscular endurance, but muscular strength and flexibility need to be addressed separately.

The ACSM recommends resistance training using the “overload principle,” which involves placing habitual stress on a system, causing it to adapt and respond. For this training, it is suggested that eight to twelve repetitions of eight to ten strengthening exercises of the major muscle groups be performed a minimum of two days per week.

Flexibility of connective tissue and muscle tissue is essential to maximize physical performance and limit musculoskeletal injuries. At least one stretching exercise for each major muscle group should be executed three to four times per week while the muscles are warm. Three methods of stretching that have been designed to improve flexibility are ballistic stretching, static stretching, and proprioceptive neuromuscular facilitation (PNF). Ballistic stretching incorporates a bouncing motion and is generally prescribed only in sports that replicate this type of movement. During a static stretch, the muscles and connective tissue are passively stretched to their maximum lengths. PNF involves a contract-relax sequence of the muscle.

In addition to exercise prescription for cardiorespiratory fitness, muscular fitness, and flexibility, it is appropriate for the exercise physiologist to make recommendations concerning body composition. Exercise is an effective tool in fat loss. Dietary caloric restriction without exercise results in a greater loss of muscle mass along with fat than if exercise is part of a weight-loss program.

For persons with special health concerns, such as diabetes mellitus or high blood pressure, the exercise physiologist works with the participant’s physician. The physician prescribes necessary medications and often decides which modes of exercise are contraindicated (that is, should be avoided).

A second application, cardiac rehabilitation, takes exercise prescription a step further. Participation of a heart patient in cardiac rehabilitation is more individualized than in wellness programs. The conditions of the circulatory system, pulmonary system, and joints are only a few of the special concerns. Secondary conditions such as obesity, diabetes, and hypertension must also be considered. The responsibilities of cardiac-rehabilitation specialists include monitoring blood sugar in diabetic patients and blood pressure in all patients, especially those with hypertension. Many drugs affect heart rate or blood pressure, and most of these participants are taking more than one type of medication. Patients with heart damage caused by a heart attack may display atypical heart rhythms, which can be seen on an ECG monitor. Furthermore, the stage of recovery of the postsurgical patient is a major factor in recommending the type, frequency, intensity, and duration of exercise.

Patient education is also important. Lifestyle is usually the main factor in the development of heart disease. Cardiac patients often have never participated in a regular exercise program. They may smoke, be overweight, or have poor eating habits. Helping them to identify and correct destructive health-related behaviors is the focus of education for the heart patient.

A third application of the study of exercise physiology involves dealing with the competitive athlete. In this case, findings from the most recent research are constantly applied to yield the best athletic performance possible. A delicate balance of aerobic training, anaerobic training, strength training, endurance training, and flexibility exercises are combined with the optimum percentage of body fat, proper nutrition, and adequate sleep. The program that is designed must enhance the athletic qualities that are most beneficial to the sport in which the athlete participates.

The competitive athlete usually pushes beyond the boundaries of general exercise prescription in terms of intensity, duration, and frequency of exercise performance. As a result, the athlete risks suffering more injuries than the individual who exercises for health benefits. If the athlete sustains an injury, the exercise physiologist may work in conjunction with an athletic trainer or sports physician to return the athlete to competition as soon as possible.

Perspective and Prospects

The modern study of exercise physiology developed out of an interest in physical fitness. In the United States, the concern for development and maintenance of physical fitness was well established by the end of the twentieth century. As early as 1819, Stanford and Harvard Universities offered professional physical-education programs. At least one textbook on the physiology of exercise was published by that time.

Much of the pioneer work in this field, however, was done in Europe. Nobel Prize–winning European research on muscular exercise, oxygen utilization as it relates to the upper limits of physical performance, and production of lactic acid during glucose metabolism dates back to the 1920s.

In the early 1950s, poor performance by children in the United States on a minimal muscular fitness test helped lead to the formation of what became known as the President’s Council on Physical Fitness and Sport. Concurrently, a significant number of deaths of middle-aged American males were found to be caused by poor health habits associated with coronary artery disease. A need for more research in the areas of health and physical activity was recognized by the mid-1960s. The subsequent research was facilitated by the existence of fifty-eight exercise-physiology research laboratories in colleges and universities throughout the country. Organizations such as the American Physiological Society (APS), the American Alliance of Health, Physical Education, Recreation and Dance (AAHPERD), and the American College of Sports Medicine (ACSM) were established by the mid-1950s. In an effort to ensure that well-trained professionals were involved in cardiac-rehabilitation programs, the ACSM developed a certification program in 1975. Certifications for fitness personnel were added later.

Increasingly sophisticated testing equipment should lead to a better understanding of fundamental physiological mechanisms, allowing practitioners to be more effective in measuring physical fitness and prescribing exercise programs. Health maintenance has become a priority as the number of adults over the age of fifty continues to increase. Advances in medical techniques also increase the survival rate of victims of heart attacks, creating a need for more cardiac-rehabilitation programs and practitioners. Health-care professionals and the general population need to be made more aware of the benefits of exercise for the maintenance of good health and the rehabilitation of individuals with medical problems.

Bibliography

Brooks, George A., and Thomas D. Fahey. Fundamentals of Human Performance. New York: Macmillan, 1987. Print.

Clarke, David C., and Philip F. Skiba. "Rationale and Resources for Teaching the Mathematical Modeling of Athletic Training and Performance." Advances in Physiology Education 37.2 (2013): 134–52. Print.

Issurin, Vladimir. "Training Transfer: Scientific Background and Insights for Practical Application." Sports Medicine 43.8 (2013): 675–94. Print.

Kenney, W. Larry, Jack H. Wilmore, and David L. Costill. Physiology of Sport and Exercise. 5th ed. Champaign: Human Kinetics, 2012. Print.

Kraemer, William J., Steven J. Fleck, and Michael R. Deschenes. Exercise Physiology: Integrating Theory and Application. Baltimore: Lippincott, 2012. Print.

McArdle, William D., Frank I. Katch, and Victor L. Katch. Exercise Physiology: Nutrition, Energy, and Human Performance. 8th ed. Philadelphia: Lippincott, 2015. Print.

Pescatello, Linda S., et al., eds. ACSM’s Guidelines for Exercise Testing and Prescription. 9th ed. Philadelphia: Lippincott, 2014. Print.

Plowman, Sharon A., and Denise L. Smith. Exercise Physiology for Health, Fitness, and Performance. 4th ed. Baltimore: Lippincott, 2014. Print.

Powers, Scott K., and Edward T. Howley. Exercise Physiology: Theory and Application to Fitness and Performance. 8th ed. New York: McGraw, 2012. Print.

Swain, David P., et al., eds. ACSM’s Resource Manual for Guidelines for Exercise Testing and Prescription. 7th ed. Baltimore: Lippincott, 2014. Print.

What objects could represent Firegirl?

1. The first object in the story that might represent Firegirl, or Jessica, is the broken prayer ring. Look in Chapter 9, where Jessica is present at school for the first time at St. Catherine's when the kids are supposed to form a circle, hold hands, and say a prayer. Although Tom, the narrator, manages to hold Jessica's hand on one side, Jeff is on her other side and refuses. (He's the less sensitive of the two boys, easily grossed out, and only interested in Jessica to satisfy his own morbid curiosity.) 

A prayer ring is supposed to be a symbol of unity, but when Jeff won't complete the circle by holding Jessica's burned hand, the circle is broken and now represents a lack of unity: a failure for the kids to make a connection, both literally in the prayer circle and figuratively by developing friendships with Jessica. Therefore, the broken prayer ring, by being damaged and incomplete, represents Jessica at the beginning of the story.

(Whoever designed the cover art for my copy of Firegirl must have thought the broken prayer ring was an important symbol, too. The cover has an image of paper children all connected, except for a gap in the middle where a burnt paper child is only holding hands with the child to her right and not to her left.)

2. The photograph of "Anne" is a representation of both Jessica's past and of what Jessica longs to be. We see this item as Jessica accidentally drops it from her pencil case in Chapter 11. Anne is supposedly Jessica's sister who, we assume at this point, died in the fire that injured Jessica so badly. Because we see "Anne" smiling beautifully, looking happy, and playing tennis in the photo, and because Jessica carries it around with her wherever she goes, we can interpret the photo as a symbol of everything Jessica has lost and everything she wishes she could get back, namely, her own normal self. So it makes sense in Chapter 14 when we find out from Jessica's dad that there never was an Anne. It's a photo of Jessica before the fire.

3. Jessica's open bedroom window represents her longing for escape from her situation. By Chapter 13, we know that she feels trapped inside her damaged body and trapped inside her home with a mom she hates. But she likes to leave her window open, for the fresh air and the possibility of escape that it brings:

"...it feels like I could glide right out over the yard. Not fly really, but just sort of swim in the air. Slow."

"The wind goes through the leaves in the trees and I feel like I could move out into it."

Thankfully, her new and tentative friendship with Tom helps ease Jessica's sense of isolation and unhappiness. You might liken him to the breeze that rolls into her window.

Do you think Shylock deserves the treatment given to him in the trial scene in The Merchant of Venice? Act 4, scene 1.

You could go either way in your answer to this question.  It does not matter if you think yes or no.  What matters is that you back up your position with reasons and evidence from the text.  

You could answer yes, and say that Shylock deserves the treatment in the court proceedings because Shylock is a jerk.  He's mean to his daughter, he hates people simply based on their religion, and he charges ridiculous interest on his loans in order to make more money.  

You could say no, Shylock does not deserve the treatment he gets at the trial, because he is on the receiving end of an intentional manipulation of the laws.  He is strung along and made to believe one thing only to have the situation pull a complete 180 a minute later.   The court proceeding is a mockery of a judicial system, and even though Shylock is a jerk, he still deserves a fair day in court. 

What is the definition of a function?

As described above, a function is a rule that creates correspondence between an element of set x, called domain, and an element of set y, called range. The function is usually denoted as y = f(x), where f(x) means: if one takes x and applies the rule f, y is obtained.

Functions can be given in various forms:

1) Verbal description. For example, one's weekly salary depends on the number of hours worked per week, if one makes $15 an hour.

2) Formula. For example, y = 2x + 3.

3) Table, or set of ordered pairs. For example, {(1, 2), (2, 3), (-1, 4)}. The first number in a pair is an element of x and the second number is an element of y.

4) Graph.

However, not every rule, or every correspondence between an element of set x and an element of set y is a function. In a function, each element of x can correspond to only one element of y. If this is not the case, the correspondence is called a relation, but it is not a function.

For example, the set of ordered pairs{(1, 2), (1, 3), (2, 5)} is NOT a function because for x = 1 there are two values of y: y = 2 and y = 3.

Likewise, the equation `y^2 = x^2` does NOT define a function y = f(x) because it is possible for x = 1 to have two corresponding elements of y: y = 1 and y = -1. On the graph, the curve representing this equation can be crossed by a vertical line in two places.

However, a function CAN have two different elements of x corresponding to one element of y. For example,

{(1, 2), (2, 2), (-1, 3)} is a function and `y = x^2` is a function.

What is essential tremor?

Risk Factors

A family history of tremors is the only known risk factor for essential tremor. Although the condition may occur at any age, it is more likely to occur in people older than forty years old.

Etiology and Genetics

Familial essential tremor is a condition in which multiple environmental and genetic factors play a contributing part. Approximately 50 percent of affected individuals report one or more family members who are similarly affected. The inheritance pattern may vary, but in most families an autosomal dominant mode of transmission is observed, meaning that a single copy of the mutation is sufficient to cause expression of the trait. An affected individual has a 50-percent chance of transmitting the mutation to each of his or her children. Many cases of essential tremor, however, result from a spontaneous new mutation, so in these instances affected individuals will have unaffected parents. The age of onset is variable, but virtually all individuals who carry the mutation will show some expression by age seventy.

Two genes have been identified with a direct association with essential tremor, and other genes are expected to play minor roles as well. The first gene to be discovered is known variously as either DRD3
or FET1, and it is located on the long arm of chromosome 3 at position 3q13.3. This gene encodes the dopamine receptor protein D3, which is expressed in nerve cells in the brain. It responds to the neurotransmitter dopamine and triggers a signal to produce physical movement. A mutation in the FET1 gene may cause the receptor protein to react more strongly to dopamine, causing the involuntary shaking characteristic of the condition.

The second gene shown to be associated with essential tremor is HS1BP3, found on the short arm of chromosome 2 at position 2p24.1. Its protein product is the hematopoietic-specific protein 1 binding protein 3. Localized primarily in the cerebellum region of the brain, this protein helps regulate the chemical signaling involved in coordinating movements of muscles by motor neurons. A third gene on the short arm of chromosome 4, at position 4p14, is involved in only those individuals who have both Parkinson disease and essential tremor.

Symptoms

Essential tremor is generally not serious, but its severity may vary and worsen over time. Symptoms may include a tremor that occurs when standing or moving the limbs, but not usually at rest; uncontrollable, rhythmic, up-and-down movement; shaking in hands, arms, head, voice, trunk, legs, or feet on both sides; shaking only in certain positions or during activity; and trouble with fine motor skills, such as drawing, sewing, or playing an instrument. Other symptoms may include shaking that gets worse from caffeine, stress, fatigue, or heat; hearing loss (some cases are associated with hearing loss); and problems with social, functional, or occupational abilities (more severe cases interfere with these abilities). To be considered as having essential tremor, an individual’s tremors must not be related to other health conditions.

Screening and Diagnosis

The doctor will ask about a patient’s symptoms and his or her medical and family history. The doctor will also do a physical exam, paying particular attention to the patient’s central nervous system. At this time, there are no special tests to diagnose essential tremor. However, patients may have blood, urine, or other tests, such as a magnetic resonance imaging (MRI) scan, to rule out other causes, like Parkinson disease, elevated thyroid hormone, low blood sugar, stroke, and medications.

Treatment and Therapy

Most people with essential tremor do not require treatment. Mild tremors may be relieved or even eliminated by simple measures, including staying well rested, avoiding caffeine, avoiding stimulants often found in over-the-counter medications such as cold remedies, and avoiding temperature extremes.

Individuals should talk to their doctors about any medications that may be contributing to their symptoms. If a patient’s symptoms are troubling, treatment options that may be helpful include beta blockers, such as propranolol (a blood pressure medication); antiseizure medications, such as primidone (Mysoline), gabapentin (Neurontin), or topiramate (Topamax); and sedatives (benzodiazepines).

Botulinum injections may be used in rare situations. In rare cases where tremors are very disabling and medications do not help, surgery may be an option. Two approaches are possible: deep brain stimulation (DBS) and thalamotomy. DBS transmits painless electrical pulses to the brain, interrupting faulty signals. Thalamotomy destroys a tiny part of the brain generating the tremors; it is less commonly performed than DBS.

Prevention and Outcomes

There is no known way to prevent essential tremor.

Bibliography

Jankovic, J., and K. M. Shannon. “Movement Disorders.” Neurology in Clinical Practice. Ed. Walter G. Bradley et al. 6th ed. 2 vols. Philadelphia: Elsevier, 2012. Print.

Lorenz, D., and G. Deuschl. “Update on Pathogenesis and Treatment of Essential Tremor.” Current Opinion in Neurology 20.4 (2007): 447–52. Print.

Lyons, Kelly E., and Rajesh Pahwa, eds. Handbook of Essential Tremor and Other Tremor Disorders. Boca Raton: Taylor, 2005. Print.

Plumb, Mark, and Peter Bain. Essential Tremor: The Facts. New York: Oxford UP, 2007. Print.

Stuart, Annie. "Benign Essential Tremor." Health Library. EBSCO Information Services, 12 Feb. 2014. Web. 22 July 2014.

"Tremor." MedlinePlus. US Nat'l. Lib. of Medicine, 22 May 2014. Web. 22 July 2014.

What is a sentence of Chapter 7 of Bud, Not Buddy by Christopher Paul Curtis that has the sense of touch?

That's a great chapter.  It's the chapter where Bud goes into the library to find Miss Hill, and the reader learns Bud's rule about people saying "haven't you heard?"  

The chapter is also a feast for the senses, because Bud describes the library's looks, smells, and feel.  

The second sentence of the chapter provides a good sentence that highlights Bud's sense of touch.  

The air in the library isn't like the air anywhere else, first it's always cooler than the air outside, it feels like you're walking into a cellar on a hot July day, even if you have to walk up a bunch of stairs to get into it.

Bud could have told his readers that the air conditioning was on, but he doesn't.  He describes what the air feels like on his skin, and he uses a familiar analogy to anybody that has ever been in a house with a basement.

I found it odd that the third story of a building could be so cool during that time in history, because I didn't think that air conditioning had been invented yet.  But it turns out that air conditioning was invented in 1902, so it is more than likely that the air was so cool because the building had air conditioning. 

The rest of the narration about the library focuses mainly on the smell of the library and all of its books.  

How is Romeo's attitude toward love presented in Act 1, Scene 1 and how does he use oxymoron to express his mixed emotions?

Romeo describes the fickle nature of the feud and the complex nature of love.

When Romeo sees the aftermath of the marketplace brawl, he understands what happened immediately. He is a Montague and knows about such brawls. Romeo is a sensitive young man, though, and knowing what happened upsets him. He expresses the depth of his emotions through oxymoron, a figure of speech involving two contradictory or opposing elements such as "loving hate," as can be seen throughout his following speech:

Here's much to do with hate, but more with love.
Why, then, O brawling love! O loving hate!
O any thing, of nothing first create!
O heavy lightness! serious vanity!
Mis-shapen chaos of well-seeming forms!
Feather of lead, bright smoke, cold fire,
sick health . . . (Act 1, Scene 1)

Romeo has a point. The brawls, while serious, come from a place of ridiculousness and vanity. There is no substance behind them. People attack each other for no reason, because they like to fight or because they are blinded by the fact that the other family is the enemy.

Romeo does not have personal enemies. He is a lover, not a fighter. Poor Romeo is suffering from his unrequited love of Rosaline. He is in a low place. When he sees the violence, he ponders the connection between love and hate. He speaks to Benvolio, his cousin and friend, about the meaning of and pain associated with love.

Love is a smoke raised with the fume of sighs;
Being purged, a fire sparkling in lovers' eyes;
Being vex'd a sea nourish'd with lovers' tears . . . (Act 1, Scene 1)

Love can be fickle. Someone can be in love with you one day and no longer in love with you the next. That is just part of being young, or part of being human. Romeo is saying that love can be temporary and frustrating, even though it can also be powerful.

Is the play Romeo and Juliet relevant for teenagers today?

Although William Shakespeare's famous play, Romeo and Juliet, is set several centuries ago, I think many of its themes are still quite relevant to the lives and interests of young people today. Let's consider some of the major dynamics of the play:

• Romeo and Juliet come from feuding families and are essentially forbidden to be together.


• Juliet's parents want to secure her future by marrying her to the well-off Paris.


• Romeo and Juliet are young adults who wish to establish their independence and find happiness.

I think modern-day teenagers can relate to some extent to each of these situations. Many young people want things their parents have forbidden, and are willing to go to extreme lengths to experience their heart's desires. Part of this willingness is because young adults are bridging the time and responsibilities of childhood and adulthood; at this age, they're supposed to be trying to make decisions for themselves. At the same time, parents believe they have their children's best interests at heart and may make a decision they feel is appropriate even if it means upsetting their children.

As for the grand theme of love, I think love regularly makes fools of people of all ages. If nothing else, perhaps teenagers can relate to Romeo and Juliet's passion for one another and recognize that repeating their decisions of faking their deaths and running away is not a good idea.

`a_1 = 0, a_2 = 8, a_4 = 30` Find a quadratic model for the sequence with the indicated terms.

The given sequence is:

`a_1 = 0` ,   `a_2=8` ,   `a_4=30`

To determine its quadratic model, apply the formula

`f(n) = an^2 + bn + c`

where f(n) represents the nth term of the sequence, `f(n)=a_n` .

So, plug-in the first term of the sequence.

`0=a(1)^2 + b(1) + c`

`0=a+b+c `               (Let this be EQ1.)

Plug-in too the second term of the sequence.

`8=a(2)^2+b(2)+c`

`8=4a+2b+c`          (Let this be EQ2.)

And, plug-in the 4th term of the sequence.

`30=a(4)^2+b(4)+c`

`30=16a+4b+c `        (Let this be EQ3.)

To solve for the values of a, b and c, apply elimination method of system of equations.  In this method, a variable or variables should be removed.

Let's eliminate c. To do so, subtract EQ1 from EQ2.

EQ2:       `8=4a+2b+c`

EQ1:   `-(0=a+b+c)`

`----------------`

               `8=3a+b`          (Let this be EQ4.)

Let's eliminate c again. This time, subtract EQ2 from EQ3.

EQ3:     `30=16a+4b+c`

EQ2:   `-(8=4a+2b+c)`

`----------------`

                `22=12a+2b`

And this simplifies to:

`22/2=(12a+2b)/2`

`11=6a+b `          (Let this be EQ5.)

Then, eliminate b. To do so, subtract EQ4 from EQ5.

EQ5:      `11=6a+b`

EQ4:   `-(8=3a+b)`

`--------------`

               `3=3a`

Isolating the a, it becomes:

`3/3=(3a)/3`

`1=a`

Then, plug-in the value of a to either EQ4 or EQ5. Let's use EQ4.

`8=3a+b`

`8=3(1) + b`

`8=3+b`

`8-3=3-3+b`

`5=b`

And, plug-in the values of a and b to either EQ1, EQ2 or EQ3. Let's use EQ1.

`0=a+b+c`

`0=1+5+c`

`0=6+c`

`0-6=6-6+c`

`-6=c`

Now that the values of a, b and c are known, plug-in them to:

`f(n)=an^2+bn+c`

`f(n)=(1)n^2+5n+(-6)`

`f(n)=n^2+5n-6`

Replacing the f(n) with an, it becomes:

`a_n=n^2+5n-6`

Therefore, the quadratic model of the sequence is `a_n=n^2+5n-6` .

There is a person who is in the hospital in a persistent vegetative state. He can breath on his own but eats through a feeding tube. There is only...

The problem here is that analyzing the utilitarian calculus of happiness in this case depends on an assumption about Patient X, the person in the vegetative state. The problem is that persistent vegetative state, or PVS, is a complex diagnosis. If it is caused by certain types of trauma to the brain or sustained oxygen deprivation there is no chance that Patient X would regain consciousness. In other circumstances, where "locked-in syndrome" may have been misdiagnosed as PVS, there may be a possibility of gaining consciousness. Before one can make ethical judgments, it is important to ascertain all the facts. 

The next question of fact is whether Person X is experiencing happiness or well-being. If not, a utilitarian would see no ethical dilemma in removing life support. If the person was not experiencing some form of happiness, then the parents' economic well-being would take priority. Of course, that does not solve the issue of how one can determine the degree of happiness experienced by someone who cannot communicate. 

The next issues are ones of definition. Of one believes that well-being requires awareness, a PVS patient cannot experience well-being and therefore should not be kept alive if there is no chance of recovery. In some religious traditions, though, the soul is considered the seat of well-being and is considered independent of "mind". In such traditions, as long as the soul has not left the body, the utilitarian calculus would favor keeping the person on life support. 

What the complexity of these issues suggests is that all people should think carefully about what they would wish were they to be in such circumstances and write out legally binding advance directives specifying their wishes so that they do not burden relatives with having to make such painful decisions for them. 

Find the area bounded by y=x-2 and y=x^2-3

Hello!

The graph of the first function, `f(x)=x-2,` is a straight line, the graph of the second function, `g(x)=x^2-3,` is a parabola branches up. These graphs have two intersections, `(x_1,y_1)` and `(x_2,y_2),` we'll find them. The figure whose area we have to compute lies between these points of intersection, and the first graph is over the second between `x_1` and `x_2.`

Therefore the area `A` is equal to  `int_(x_1)^(x_2) (f(x)-g(x)) dx.`

To find `x_1` and `x_2` we have to solve the equation `f(x)=g(x),` i.e. `x-2=x^2-3,` or `x^2-x-1=0.` It is a quadratic equation and `x_1=(1-sqrt(5))/2,`  `x_2=(1+sqrt(5))/2.`

Thus `A=int_(x_1)^(x_2) (f(x)-g(x)) dx=int_(x_1)^(x_2) (-x^2+x+1) dx=`

`=(-1/3 x^3+1/2 x^2+x)|_(x_1)^(x_2)=-1/3(x_2^3-x_1^3)+1/2(x_2^2-x_1^2)+(x_2-x_1).`

We can simplify this slightly,

`A=(x_2-x_1)(-1/3(x_1^2+x_1x_2+x_2^2)+1/2(x_2+x_1)+1)=`

`=sqrt(5)*(-1/3*(3-1)+1/2+1)=sqrt(5)*(3/2-2/3)=sqrt(5)*5/6 approx 1.86.`

This is the answer.

What is special about the cells of Henrietta Lacks?

Most human cells are very difficult to grow in a laboratory environment. Most cells die quickly or only divide a few times once they are placed in culture. In the 1950’s, doctors performed a biopsy for cervical cancer on a patient named Henrietta Lacks. It was discovered that these cells were able to be grown continuously under laboratory conditions. For all practical purposes the cell stocks derived from Henrietta Lacks’ biopsy were immortal.

These cell stocks became known as “HeLa” cells. HeLa cells enable scientists to always have cell stocks available for experimentation. Furthermore, scientists from different labs are able to perform experiments on the same cells and compare results.

HeLa cells have been used to: explore cell growth and differentiation, develop vaccines, and devise new laboratory techniques. At the time of her biopsy, there were no rules about the use of left over tissue. Consequently, HeLa cells were grown and used without permission from Henrietta Lacks.

How would the application of the Beatitudes guide Christians in addressing youth homelessness?

The Beatitudes focus largely on the poor and marginalized in society. According to Jesus, these poor and marginalized people, while not well-regarded on Earth, are thought of highly in Heaven. If a young person is homeless, that person can usually be assumed to be "poor in spirit," which is one of the groups referenced by Jesus. The "poor in spirit" are supposed to receive the Kingdom of Heaven. Reaching the Kingdom of Heaven is generally considered to be the goal of Christians on Earth, so if people who are poor in spirit are making it to Heaven, everyone else should try to learn from them so they can reach Heaven, too. Learning from someone happens best when you respect that person's background, so, in the case of youth homelessness, someone trying to apply the Beatitudes would not only try to help homeless young people, but also be respectful about their situations and to them.

What is digestion?

Structure and Functions

In the most general terms, digestion is a multiple-stage process that begins by breaking down foodstuffs taken in by an organism. Some specialists consider that the actual process of digestion occurs after this breaking-down stage, when essential nutritional elements are absorbed into the body. Even after division of the digestive process into two main functions, there remains a third, by-product stage: disposal by the body of waste material in the form of urine and feces.

Several different vital organs, all contained in the abdominal cavity, contribute either directly or indirectly to the digestive process at each successive stage. Certain imbalances in the functioning of any one of these organs, or a combination, can lead to what is commonly called indigestion. Chronic imbalances in the functioning of any of the key digestive organs—the stomach, small intestine, large intestine (or colon), liver, gallbladder, and pancreas—may indicate symptoms of diseases that are far more serious than mere indigestion.

In a very broad sense, the process of digestion begins even before food that has been chewed and swallowed passes into the stomach. In fact, while chewing is underway, a first stage of glandular activity—the release of saliva by the salivary glands into the food being chewed (a process referred to as intraluminal digestion)—provides a natural lubricant to help propel masticated material down the esophagus. Although the esophagus does not perform a digestive function, its muscular contractions, which are necessary for swallowing, are like a preliminary stage to the muscular operation that begins in the stomach.

The human stomach has
two main sections: the baglike upper portion, or fundus, and the lower part, which is twice as large as the fundus, called the antrum. The function of the fundus is essentially to receive and hold foods that reach the stomach via the esophagus, allowing intermittent delivery into the antrum. Here two dynamic elements of the breaking-down process occur, one physical, the other chemical. The muscular tissue surrounding the antrum acts to churn the partially liquefied food in the lower stomach, while a series of what are commonly called gastric juices flow into the mixture held by the stomach.

The most active element that is secreted from special parietal cells in the mucous membranes lining the stomach is hydrochloric acid. The possibility of damage to the stomach lining is minimized (but not removed entirely) first by the chemical reaction between the acid and the mildly alkaline chewed food and second by the presence of other gastric juices in the antrum. Primary among these is the enzyme pepsin, which is secreted by a different set of specialized cells in the gastric lining. Secretions of both hydrochloric acid and pepsin become mixed and interact chemically with food materials, while the antrum itself moves in rhythmic pulses caused by muscular contractions (peristalsis). One of the key functions of pepsin during this stage is to break down protein molecules into shorter molecular strings of less complicated amino acids, which eventually serve as building material for many body tissues.

At a certain point, food materials are sufficiently reduced to pass beyond the antrum into the duodenum, the first section of the small intestine, where a different stage in the digestive process takes place. At this juncture, the partially broken-down food material is referred to as chyme. The transfer of food from one digestive organ to another is actually monitored by a special autonomic nerve, called the vagus nerve, which originates in the medulla at the head of the spinal cord. Although the vagus nerve innervates a number of vital zones in the abdominal cavity, its function here is quite specific: It adjusts the intensity of muscular movement in the stomach wall and thus limits the amount of food passing into the small intestine.

The exact amount of food that is allowed to enter the intestinal tract represents only part of the essential question of balance between agents contributing to the digestive process. The presence of a now slightly acidic food-gastric juice mixture in the duodenum sparks what is called an enterogastric reflex. Two hormones, secretin and cholecystokinin, begin to flow from the mucous membranes of the duodenum. These hormones serve to limit the acidic strength of stomach secretions and trigger reactions in the liver, gallbladder, and pancreas—other key organs that contribute to digestion as the chyme passes through the intestines.

While in the compact, coiled mass of the small intestine (compared to the thicker, but much shorter, colon, or large intestine), food materials, especially proteins, are broken down into one of twenty possible amino acid components by the chemical action of two pancreatic enzymes, trypsinogen and chymotrypsinogen, and two enzymes produced in the intestinal walls themselves, aminopeptidase and dipeptidase. It is interesting to note that the body, which is itself in large part constructed of protein material, has its own mechanism to prevent protein-splitting enzymes from devouring the very organs that produce them. Thus, when they leave the pancreas, both trypsinogen and chymotrypsinogen are inactive compounds. They become active “protein-breakers” only when joined by another enzyme—enterokinase—which is secreted from cells in the wall of the small intestine itself.

Other nutritional components contained in chyme interact chemically with other specialized enzymes that are secreted into the small intestine. Carbohydrate molecules, especially starch, begin to break down when exposed to the enzyme amylase in saliva. This process is intensified greatly when pancreatic amylase flows into the small intestine and mixes with the chyme. The products created when carbohydrates break down are simple sugars
, including disaccharides and monosaccharides, especially maltose. As these sugars are all broken down into monosaccharides, a final process that occurs in the wall of the small intestine itself (which contains more specialized enzymes such as maltase, sucrase, and lactase), they become the most rapidly assimilated body nutrients.

The process needed to break down fats is more complicated, since fats are water insoluble and enter the intestine in the form of enzyme-resistant globules. Before the fat-splitting enzyme lipase can be chemically active, bile, a fluid produced by the liver and stored in the gallbladder, must be present. Bile serves to dissolve fat globules into tiny droplets that can be broken down for absorption, like all other nutritive elements, into the body via the epithelial lining of the intestinal wall. Such absorption is locally specialized. Iron and calcium pass through the epithelial lining of the duodenum. Protein, fat, sugars, and vitamins pass through the lining of the jejunum, or middle small intestine. Finally, salt, vitamin B12, and bile salts pass through the lining of the lower small intestine, or ileum.

It is this stage that many scientists consider to be the true process of digestion. Absorption occurs through enterocytes, which are specialized cells located on the surface of the epithelium. The surface of the epithelium is increased substantially by the existence of fingerlike projections called villi. These tiny protrusions are surrounded by the fluid elements of chemically altered food. Specialized enterocyte cells selectively absorb these elements into the capillaries that are inside each of the hundreds of thousands of villi. From the capillaries, the nutrients enter the blood and are carried by the portal vein to the liver. This organ carries out the essential chemical processes that prepare fats, carbohydrates, and proteins for their eventual delivery, through the main bloodstream, to various parts of the body.

Elements that are left after the enzymes in the small intestine have done their work are essentially waste material, or feces. These pass from the small intestine to the large intestine, or colon, through a dividing passageway called the cecum. The disposal of waste materials may or may not be considered to be technically part of the main digestive process.

After essential amounts of water and certain salts are absorbed into the body through the walls of the colon, the remaining waste material is expulsed from the bowels through the rectum and anus. If any prior stage in the digestive process is incomplete or if chemical imbalances have occurred, the first symptoms of indigestion may manifest themselves as bowel movement irregularities.

Disorders and Diseases

Malfunctions in any of the delicate processes that make up digestion can produce symptoms that range from what is commonly called simple indigestion to potentially serious diseases of the gastrointestinal tract. Functional indigestion, or dyspepsia, is one of the most common sources of physical discomfort experienced not only by human beings but by most animals as well. Generally speaking, dyspepsias are not the result of organic disease, but rather of a temporary imbalance in one of the functions described above. There are many possible causes of such an imbalance, including nervous stress and changes in the nature and content of foods eaten.

The most common causes of dyspepsia and their symptoms, although serious enough in chronic cases to require expert medical attention, are far less dangerous than diseases afflicting one of the digestive organs. Such diseases include gallstones, pancreatitis, peptic ulcers (in which excessive acid causes lesions in the stomach wall), and, most serious of all, cancers afflicting any of the abdominal organs.

Dyspepsia may stem from either physical or chemical causes. On the physical side, it is clear that an important part of the digestive process depends on muscular or nerve-related impulses that move partially digested food through the gastrointestinal tract. When, for reasons that are not yet fully understood, the organism fails to coordinate such physical reactions, spasms may occur at several points from the esophagus through to the colon. If extensive, such muscular contractions can create abdominal pains that are symptomatic of at least one category of functional indigestion.

Problems of motility, or physical movement of food materials through the digestive tract, may also cause one common discomfort associated with indigestion: heartburn. This condition occurs when the system fails to move adequate quantities of the mixture of food and gastric juices, including hydrochloric acid, from the stomach into the duodenum. The resultant backup of food forces part of the acidic liquid mass into the esophagus, causing instant discomfort.

Insufficient motility may also cause delays in the movement of feces through the colon, resulting in constipation. Just as the vagus nerve monitors the muscular movements that are necessary to move food from the stomach to the small intestine, an essential gastrocolic reflex, tied to the organism’s nervous system, is needed to ensure a constant rhythm in the movement of feces into the rectum for elimination. If this function is delayed (as a result of nervous stress in some individuals, or because of the dilated physical state of the colon in aged persons), food residues become too tightly compressed in the bowels. As the colon continues to carry out its normal last-stage digestive function of reabsorbing essential water from waste material before it is eliminated, the feces become drier and even more compacted, making defecation difficult and sometimes painful.

Most other imbalances in digestive functions are chemical in nature. Highly spiced or unfamiliar foods frequently upset the balance in the body’s chemical digestion. Symptoms may appear either in the abdomen itself (in particular, a bloated stomach accompanied by what is commonly called gas, a symptom of chemical disharmony in the digestive process) or in the stool. If the chemical breakdown of chyme is incomplete because of an imbalance in the proportion (either excessive or inadequate) of enzymes secreted into the stomach or intestines, the normal process of absorption will not take place, creating one of a number of symptoms of indigestion.

The most common symptom of indigestion is diarrhea, which can result from a variety of causes. Because movement in the bowels is affected by different nerve signals, some diarrhea attacks may be linked to nonchemical reactions, such as extreme nervousness. Relaxation of the sphincter, however, as well as the rise in the contractile pressure of the lower colon that precedes defecation (the gastroileal reflex), is also affected by the presence of gastrointestinal hormones, particularly gastrin itself. An imbalance in the amount of concentration of such components in the gastrointestinal tract (attributable to incomplete digestive chemistry) tends to relax the bowels to such a degree that elimination cannot be prevented except through determined mental resistance. It is important to note that if diarrhea continues for an extended time, its effect on the body is not simply the loss of essential body nutrients that pass through the bowels without being fully digested; the inability of the colon to reabsorb into the body an adequate proportion of the water content from the feces can lead to
dehydration of the organism, especially in infants.

In most areas of the world, there is widespread consensus that treatment of indigestion is a matter of taking over-the-counter drugs whose function is to right the imbalance in some of the chemical processes described above. In theory as well as in practice, such treatments do work, since the basic chemical imbalance, if it is has not extended beyond the point of indigestion (in the case of peptic ulcers, for example), is fairly easily diagnosed, even by pharmacists. Increasingly, however, the public is becoming aware that digestion can be aided, and indigestion avoided, by paying closer attention to dietary habits, particularly the importance of increasing fiber intake to facilitate the digestive process. Critical advances are also being made in knowledge of the potentially harmful effects on digestion of chemical additives to processed foods.

Perspective and Prospects

Historical traces of the medical observation of indigestion, as well as the prescription of remedies, can be found as far back as ancient Egypt. A famous medical text from about 1600 BCE known as the Ebers Papyrus contains suggested remedies (mainly herbal drugs) for digestive ailments, as well as instructions for the use of suppositories to loosen the lower bowel. For centuries, however, such practical advice for treating indigestion was never accompanied by an adequate theoretical conception of the digestion function itself.

In the medieval Western world, many erroneous guidelines for understanding the digestive process were handed down from the works of Galen of Pergamum (129–ca. 199 CE). Galen taught that food material passed from the intestines to the liver, where it was transformed into blood. At this point, a vital life-giving spirit, or “pneuma,” gave the blood power to drive the body. Similar misconceptions would continue until, following the work of William Harvey (1578–1657), medical science gained more accurate knowledge of the circulatory function of the bloodstream. By the eighteenth century, rapid advances had been made in studies of the function of the stomach and intestines, notably by the French naturalist René de Réaumur (1683–1757), who demonstrated that food is broken down by gastric juices in the stomach, and by the Italian physiologist Lazzaro Spallanzani (1729–1799), who discovered that the stomach itself is the source of gastric juices.

It was an American army surgeon, William Beaumont (1785–1853), who wrote what became, until well into the twentieth century, the most complete medical guide to digestive functions. Beaumont carried out direct clinical observations of the actions of gastric juices in humans. He also observed the way in which the anticipation of eating can spark not only the secretion of such fluids but also the muscular stimuli that promote motility in the digestive process. Soon after Beaumont’s findings were published, the German physiologist Theodor Schwann (1810–1882) first isolated pepsin. Others would show that a variety of enzymes in the gastrointestinal tract are secreted by different organs in the abdomen, notably the pancreas.

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