Lava is rock that has undergone a physical change and has liquified. What is known about this change? The lava gained mass. The lava was...

When solid rock changes into its liquid lava state, a physical change has occurred. In a physical change, the particles of a substance rearrange, but do not change into different particles.

As heat energy is applied to a solid rock, the forces holding the particles in the rock together are disrupted and the solid rock transitions into a liquid lava state. In the liquid lava state, the particles are able to move around and slide past one another. When heat energy is removed from the liquid lava, the particles become more strongly attracted to one another and the substance transitions back into the solid rock state. Therefore, the correct answer is "The lava can cool back into rock."

According to the Law of Conservation of Mass, mass cannot be created or destroyed. Therefore, when solid rock changes into liquid rock, the mass of the rock does not change. The first and fourth answer choices are incorrect, because there cannot be any gain or loss of mass when the solid rock changes to liquid lava.

Burning of lava is an example of a chemical change. In a chemical change, the particles of a substance change into different particles. 

What is the relationship between alcoholism and genetics?

Risk Factors

Certain characteristics or factors make persons more likely to develop alcoholism; they include family history of the disorder, negative environment, emotional stress, access to alcohol, young age at first use, being in the age range of eighteen to twenty-nine, male gender, and low level of education. Persons of certain races or ethnic origins, the unmarried, and children of alcoholics are more likely to become dependent on alcohol. Mental disorders such as major depression, anxiety, bipolar disorder, and antisocial personality disorder (ASPD) are associated with the development of alcoholism and may also be hereditary. Antisocial personality disorder has been referred to as the most important risk factor for alcoholism.

Etiology and Genetics

Alcoholism is a relatively common chronic and relapsing disorder that results in significant health and social consequences. Alcohol has a relatively high addictive potential in the general population and is even higher in susceptible individuals. Several epidemiology studies have been conducted to attempt to categorize genes and characteristics related to alcohol dependence. However, much is still not known about this disease and the role of genetics in the development, course, and outcome of alcoholism.

Genes under investigation for their potential role in this disorder are typically grouped by involvement in the metabolism of alcohol, rewarding circuits, and response to alcohol dependence treatment. The enzymes responsible for hepatic alcohol metabolism are alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH); the corresponding candidate genes are ADH2*2, ADH3*1, and ALDH2*2. Protective genes (associated with reduced alcohol consumption) are ADHB*2 and are found in Asians and Israeli Jews, while ADH1C*2 appears to protect against complications related to alcoholism, such as cirrhosis and pancreatitis. Gamma-aminobutyric acid (GABA) receptors are the most important inhibitory receptors and are involved in the rewarding circuit; alcohol acts as an agonist or activator of the GABAA receptor. Scots, Germans, Native Americans, and Finns have variants of GABRA6 and GAD that are associated with alcoholism.

Alcohol increases the concentration of dopamine in the brain and is important in reinforcing its effects. A variant in the DRD2 gene of the dopamine D2 receptor may be a vulnerability gene for alcohol dependence; however, data are conflicting. Presence of the DAT1 gene (which codes for the dopamine transporter and is responsible for dopamine reuptake) is associated with worse outcomes during alcohol withdrawal, such as seizures. Many other genes are linked to physiologic markers and to the diagnosis of alcohol dependence, including HTT, CRF, CRF1, CYP2EI, GABRA1, COMT, and DRD1. Psychiatric illness and high-risk behaviors may also be genetically linked and direct persons to select environments associated with dependence.

The genes involved in the immune system and the biological clocks are also investigation for their roles in alcoholism. Research conducted in 2011 and 2012, for example, showed that inflammatory responses in the brain, which inhibit judgment, and disruptions to the circadian rhythm may increase the risk for alcohol dependence.

Another line of inquiry is the interaction between alcohol consumption and epigenetics, the way in which genes are expressed or suppressed. According to the National Institute on Alcohol Abuse and Alcoholism's 2013 report on epigenetics, researchers have found that alcohol use may impair or disrupt gene expression in the liver, gastrointestinal tract, and brain. Studies also suggest that it may play a part in the development of cancers of the liver, breast, respiratory tract, and digestive tract as well as in fetal alcohol syndrome.

Symptoms

Early behavioral symptoms of alcoholism include frequent intoxication, a pattern of heavy drinking, drinking alone or in secret, or drinking alcohol in high-risk situations (such as drinking and driving). Erratic or dramatic changes in behavior with alcohol consumption, “blacking out,” or not remembering events that occurred while drinking, may also be signs of the disorder. Symptoms of alcohol dependence may become worse over time. The physical symptoms of alcoholism are many and can include jaundice (yellowing of skin or eyes), hepatitis (enlarged liver), abdominal pain, nausea and vomiting, infections, malaise (not feeling well), weight loss, fluid retention, problems with memory, and anorexia (decreased eating). Laboratory analyses may reveal increased liver enzymes, low potassium levels, low hemoglobin and hematocrit (indicating anemia), and vitamin deficiencies.

Symptom expression of alcohol dependence may differ by culture and ethnicity, because people of different cultures may express physical and mental ailments differently. Ethnic and racial groups may respond differently to alcohol and medications used to treat alcohol dependence. Some groups may even enjoy greater protection against alcoholism as a result of their genetics. Certain ethnic groups may be more susceptible to alcoholism or related complications. For instance, vulnerability to cardiomyopathy and Wernicke-Korsakoff’s syndrome may be heritable and may vary by ethnicity. Latino men, for example, tend to show greater susceptibility to alcohol-related liver damage than do white men.

Early alcohol exposure and its interaction with genetics may lead to problems in fetal and child development. Fetal alcohol syndrome
may result when a pregnant woman drinks even a moderate amount of alcohol. Exposure to alcohol in the womb can cause mild to severe facial and dental abnormalities, mental impairment, and bone and heart problems that become more obvious and problematic as the child grows. Vision, hearing, and attention problems are also common. Children of alcoholics also can have difficulties in learning, language, and temperament because of hereditary and environmental effects of growing up in an unstable home with an alcoholic parent. In sum, parents who drink may increase the likelihood that their children will develop alcoholism through both genetic and environmental factors.

Screening and Diagnosis

Various questionnaires are commonly used to screen a person for alcoholism. Questions typically ask about the amount of alcohol consumed, how often drinking occurs, how much time is spent thinking about drinking, if withdrawal occurs after stopping drinking, and effects of drinking on personal life and health. Most persons with alcoholism will deny having the disorder, and family and friends may be questioned to support the diagnosis. Alcohol dependence is rarely diagnosed in a routine office visit. Diagnosis typically follows after a major negative health or social event occurs, such as liver disease or a motor vehicle accident. After diagnosis, patients may be subgrouped into type-I or type-II alcoholism.

Alcoholism is considered a highly heritable condition. Heritability estimates range from 40 to 70 percent, as reported by V. Nieratscker, A. Batra, and A. J. Fallgatter in the Journal of Molecular Psychiatryin 2013. According to a 2012 twin study published in the journal Evidence-Based Mental Health, the incidence of alcoholism and heritability rates were similar for both sexes.

Treatment and Therapy

Three candidate genes for alcohol treatment response are OPRM1, HTT, and COMT. Currently, treatment for alcoholism includes the use of medications such as naltrexone (opioid antagonist), acamprosate (taurine analog), or disulfuram (alcohol deterrent). Whether persons will respond to a certain medication and how long they will abstain from alcohol use may vary based on genetic makeup. Psychotherapy and behavior modification are important parts of alcohol dependence treatment. Alcoholics Anonymous has a twelve-step support program for persons with alcohol dependence.

Continued study of the genes associated with different patterns of alcohol problems, protective genetic effects in populations with exceptionally low rates of alcoholism, and genetically based interventions (such as matching pharmacotherapies to different populations of individuals to forestall the development of the problem) are assured. The study of genetics and alcoholism is also likely to encourage growth in the field of ethnopharmacology, the study of how different therapeutic drugs differentially affect members of specific ethnic groups.

Prevention and Outcomes

The best way to prevent alcoholism is to avoid the use of alcohol. Alcoholism is associated with an increased risk of hepatitis, liver cancer, abuse of other substances (such as marijuana, cocaine, sedatives, and stimulants), sexually transmitted diseases and other infections, malnutrition, psychiatric illness, and premature death. Persons with alcohol dependence are more likely to gamble, smoke cigarettes, or engage in other risky behaviors.

The presence of alcohol in modern life may have genetic roots. Historically, it helped those who could tolerate its taste and effects to survive and be selected for when others who could not do so perished as a result of consuming contaminated water. Alcohol has a complex relationship to human life, and alcoholism will be studied for some time.

Bibliography

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders: DSM-5. 5th ed. Washington: American Psychiatric Association, 2013. Print.

Goldman, David, Gabor Oroszi, and Francesca Ducci. “The Genetics of Addictions.” Nature Reviews Genetics 6 (2005): 521–31. Print.

Gorwood, Philip, Mathias Wohl, Yann L. Strat, and Frederic Rouillon. “Gene-Environment Interactions in Addictive Disorders: Epidemiological and Methodological Aspects.” Comptes rendus Biologies 330 (2007): 329–38. Print.

National Institute on Alcohol Abuse and Alcoholism. "Epigenetics—A New Frontier for Alcohol Research." Alcohol Alert 86 (2013): n. pag. Web. 16 July 2014.

National Institute on Alcohol Abuse and Alcoholism. "The Genetics of Alcoholism." Alcohol Alert 84 (2012): n. pag. Web. 16 July 2014.

Nieratschker, Vanessa, Anil Batra, and Andreas J. Fallgatter. "Genetics and Epigenetics of Alcohol Dependence." Journal of Molecular Psychiatry 1.11 (2013): 1–6. PDF file.

Plomin, Robert, and Gerald E. McClearn, eds. Nature, Nurture, and Psychology. Washington: American Psychological Association, 1993. Print.

Scholten, Amy. "Risk Factors for Alcohol Abuse and Alcoholism." Health Library. EBSCO Information Services, 1 Mar. 2013. Web. 16 July 2014.

Strat, Yann L., Nicolas Ramoz, Gunter Schumann, and Philip Gorwood. “Molecular Genetics of Alcohol Dependence and Related Endophenotypes.” Current Genomics 9 (2008): 444–51. Print.

Young-Wolff, K. C., E. Chereji, and C. A. Prescott. "Heritability of Alcohol Dependence Is Similar in Women and Men." Evidence-Based Mental Health 15.3 (2012): 57. PDF file.

Why does a relative density bottle have a narrow neck?

The narrow neck of the density bottle is to ensure that the volume of liquid inside the relative density bottle can be determined accurately.

Why is this necessary? The accuracy of the value you obtain when you are calculating the density of your liquid depends on how precisely accurate the volume of liquid in the density bottle is determined.

To ensure that the volume of liquid in the bottle is exactly what is measured, the bottle has a narrow neck through which a ground glass stopper with a fine hole is inserted. This ensures that any excess liquid rises through this hole and out of the bottle when the bottle is filled with liquid. This way, you are sure to get exactly the same volume of liquid each time it is filled.

Human error in gauging the level of liquid in the container is also eliminated, when compared with taking the same measurement using a jar with a larger cross sectional area.

What are foot disorders?

Because of the constant and heavy use of feet by humans as bipeds, they are prone to many problems. In spite of what is commonly believed, most cases of foot bone and joint abnormalities are developmental in origin instead of being caused by poorly fitting footwear.

Developmental, muscle, and bone disorders of the feet.

Clubfoot, also called talipes, is one of the developmental, or congenital, disorders affecting the feet. It occurs in approximately one of every one thousand live human births and is characterized by deformities such as the foot turning down and under, such that a child will walk on the top of his or her foot. Over time, tendon and ligament contraction reinforces the deformity; thus, either casting or surgery is needed for realignment.

Flat foot, or pes planus, is an abnormally flat arch in the foot, accompanied by a characteristic gait, both of which can occur in varying degrees. Muscle weakness, incorrect weight-bearing, a short Achilles tendon, and developmental defects may all contribute to this deformity. Flat foot may or may not produce a pathologic condition such as arthritis.

A bunion is the relocation of bone from the first metatarsal to the inner portion of the joint connecting it to the big toe. This prominence at the base of the big toe makes the soft tissue in the area subject to pressure from shoes, causing swelling and pain in the protective sac above the metatarsophalangeal joint in a condition called
bursitis. Cortisone injections may relieve symptoms, but surgery is required in extreme cases to realign the first metatarsal. Flat foot usually accompanies bunions and is a factor in their development.

Muscular imbalances inherent in the foot are the reason for the curvature of the individual bones of the toes. Abnormally curved bones produce hammertoe, or claw toe, which usually requires little treatment other than a padding of the shoes to avoid corn or callus development. Excessive muscle tension at the heel can produce bony growths called heel spurs or calcaneal exostoses. Inflammation may develop in a neighboring joint’s bursa, causing a throbbing pain.

Inflammation of the calcaneus or heel bone can occur in childhood while the heel is still fusing from the two bones that constitute the heel. When a piece of separated bone, called an apophysis, becomes inflamed, apophysitis occurs. This condition can injure the connecting, softer cartilage between the two, not-yet-connected, bones. Apophysitis usually disappears as children grow and the heel fuses whole.

Nerve and skin disorders of the feet.
Factors including footwear, the structures of the foot itself, and harmful external forces acting on the foot may all contribute to irritation and/or damage to the nerves of the foot. Morton’s neuroma is the thickening of the nerve located between the metatarsals of the third and fourth toes, followed by the formation of a small benign tumor. Painful burning, numbness, or tingling sensations may be alleviated by wearing more comfortable footwear or by the surgical removal of the tumor. Tarsal tunnel syndrome occurs when a nerve traveling along the bottom of the foot through a channel called the tarsal canal becomes compressed and damaged. Cortisone injections into this canal can relieve pressure on the nerve, and surgery can be used to treat severe cases.

The skin of the foot is subject to much pressure and rubbing; thus, it responds by producing changes, termed dermatologic disorders, which themselves cause pain. A corn, or heloma, is a small, sharply defined, raised area of thickened skin containing much of the fibrous protein called keratin. Calluses are also composed of keratin but are flatter and do not possess the defined borders of corns. Both types of thickened keratinized skin are usually attributed to incorrect positioning of the underlying bone.

Warts, or verrucae, are actually skin tumors caused by the human papillomavirus. They occur most commonly on the sole of the foot, where they are named plantar warts. Warts can be transmitted from person to person, and the lymphatic communication between warts within an individual explains their ability to spread. Warts on the foot are invariably benign, however, and should not be treated with x-ray or radium therapy lest the surrounding areas undergo change themselves and eventually produce tumors.

Dermatitis venenata is often caused by chemicals used in the binding or dyeing of shoes. Angiokeratoma is a lesion on the bottom of the foot commonly mistaken for a wart. Fibroma is the name of the benign growth that may spread under the toenails as a result of insect bites in the vicinity or manifestations of other skin diseases.

Ingrown toenails
, or onychocryptoses, occur when the free end of the toenail penetrates the surrounding soft tissue. Reasons for this painful disorder are commonly badly fitted footwear, nail disease, and foot or nail structural abnormalities.

Systemic diseases affecting the feet.
Rheumatoid arthritis is a condition involving connective tissue, unknown in origin, in which the synovial
membrane of joints proliferates while invading and even destroying cartilage and bone. Women acquire this disease three times more often than do men. Steroid hormones are sometimes applied to aid in the treatment of rheumatoid arthritis, but gold salt injection is the only therapy resulting in a permanent cure. The chances of a cure are greater when this disease occurs in children. The condition is then known as juvenile rheumatoid arthritis, or Still’s disease.

Several normally fatal diseases may accompany rheumatoid arthritis. Systemic
lupus erythematosus can be masked by the arthritic condition until inflammation spreads to small arteries of the body’s organs. Polyarteritis nodosa also involves arteries throughout the body, and its true diagnosis may be prevented by the misleading arthritic condition.
Scleroderma involves the thickening of the skin on the face, hands, and feet; depigmentation; loss of hair; and lesions.
Sarcoidosis manifests itself in the hands and feet and causes microscopic lesions in the bone that eventually become visible by x-ray examination. Henoch-Schönlein syndrome is an allergic reaction that can resemble the synovitis of rheumatic fever.

Rheumatic fever affects fibrous tissues in a widespread fashion involving the joints and later the heart. It is related to
streptococcal infections and occurs as a migrating arthritis producing no lasting joint damage in the feet, but it can cause permanent damage to the cardiac valve.
Osteoarthritis causes the degeneration of cartilage and the overgrowth of bone surfaces. The effects of this condition are limited to the joints, unlike rheumatoid arthritis, which can spread to nearby cartilage and bone. Staphylococci, streptococci, and coliform bacteria are the infective agents involved in pyogenic arthritis. In this condition, the organism is carried by the blood to the joint interior. Ulcers of the feet may be caused by a variety of conditions, including diabetes mellitus, syphilis, anemia, and
leprosy.

If there is sustained pain in the foot or ankle with no known cause such as injury, a continuously low leukocyte count, and negative laboratory tests for the presence of bacteria, then a viral infection is likely present. An elevated leukocyte count is often indicative of a bacterial infection.

American Podiatric Medical Association. http://www .apma.org.

Copeland, Glenn, and Stan Solomon. The Foot Doctor: Lifetime Relief for Your Aching Feet. Rev. ed. Toronto, Ont.: Macmillan Canada, 1996.

Lippert, Frederick G., and Sigvard T. Hansen. Foot and Ankle Disorders: Tricks of the Trade. New York: Thieme, 2003.

Lorimer, Donald L., et al., eds. Neale’s Disorders of the Foot. 7th ed. New York: Churchill Livingstone/Elsevier, 2006.

Mooney, Jean. Illustrated Dictionary of Podiatry and Foot Science. New York: Churchill Livingstone, 2009.

Rose, Jonathan D., Vincent J. Martorana. The Foot Book: A Complete Guide to Healthy Feet. Baltimore: Johns Hopkins University Press, 2011.

Thordarson, David B. Foot and Ankle. 2nd ed. Philadelphia: Wolters Kluwer/Lippincott, Williams, & Wilkins, 2013.

Van De Graaff, Kent M. Human Anatomy. 6th ed. New York: McGraw-Hill, 2002.

What are biopesticides?

Bacillus thuringiensis

Hungry insects are the bane of gardeners, since their appetite results in defoliation of the crops. This problem is worsened for farmers, whose livelihoods depend on keeping fields free of destructive insects. Although effective, chemical pesticides have a variety of drawbacks that include contamination of surface and groundwater and adverse health effects on noninsect species, including humans. The increasing popularity of organically grown produce that is untreated by chemicals is indicative of the wariness of consumers concerning human-made pesticides. In response to consumer concern over the safety of chemical pesticides, agricultural biologists have turned to nature to solve pest problems. Biopesticides are naturally derived insecticides. The process of evolution has produced biopesticides that are very specific and effective in their activity. A biopesticide may be sprayed directly on crops or may be genetically engineered to be produced by a crop itself.

One of the oldest commercial biopesticides is a bacterium called Bacillus thuringiensis (Bt). Since the 1950s, Bt has been used on crops susceptible to destruction by insect larvae. Bt is a spore-forming bacterium, meaning it is capable of producing an environmentally hardy form that protects the genetic material from adverse conditions. When conditions improve, the spore can germinate to reestablish the normally growing and dividing form of the organism. The basis of Bt’s action is the ingestion of the spores by the feeding insect larvae. During the sporulation process, Bt produces a protein crystal. When the protein is synthesized by the bacteria, it is an inactive form known as a proenzyme. After being digested by a larva, enzymes in the larval gut cleave the proenzyme into an active version that kills the larva by binding to receptors in the insect’s midgut cells and blocking those cells from functioning. Only caterpillars (tobacco hornworms and cotton bollworms), beetles, and certain flies have the gut biochemistry to activate the toxin. The toxin does not kill insects that are not susceptible, nor does it harm vertebrates in any way. This makes Bt a very specific pesticide.

Initially, Bt was expensive and remained active following spraying for only a relatively short time. These obstacles were overcome in the early 1990s, when scientists utilized genetic engineering technology to produced transgenic cotton plants that generated their own Bt toxin. The toxin gene was first isolated from Bt cells and ligated (enzymatically attached) into a Ti plasmid. A Ti plasmid is a circular string of double-stranded DNA that originates in the Agrobacterium tumefaciens
bacteria. A. tumefaciens has the ability to take a portion of that Ti plasmid, called the T-DNA, and transfer it and whatever foreign gene is attached to it into a plant cell. Cotton plants were exposed to A. tumefaciens carrying the toxin gene and were transformed. The transgenic plants synthesized the Bt toxin and became resistant to many forms of larvae. This approach has become known as plant-incorporated bioprotectants.

Many crystal toxins have been isolated from various strains of Bt. These toxins make up a large collection of proteins active against pests from nematodes to aphids. Researchers are in the process of reengineering the toxin genes to improve upon their characteristics and to design better methods of transporting genes from one Bt strain to another.

Other Biopesticides

Several species of fungi are toxic to insects, including Verticillium lecanii
and Metarhizium anisopliae. Natural fungicides that have been discovered include oils of tea tree, cinnamon, jojoba, neem, and rosemary.

In the mid-1990s, a viral biopesticide called baculovirus became widely popular. Baculoviruses are sprayed onto high-density pest populations just like chemical pesticides. Baculoviruses have several advantages over conventional pesticides. The most important advantage is their strong specificity against moths, sawflies, and beetles but not against beneficial insects. Also, viruses, unlike bacteria, tend to persist in the environment for a longer period. Finally, baculoviruses are ideal for use in developing countries because they can be produced cheaply and in great quantity with no health risks to workers. One limitation of baculovirus is that it must be administered at a certain time and location to be effective. Rather than spraying onto a crop and killing the insects that subsequently feed, baculovirus needs to be applied directly to the target insect population. Knowledge of insect behavior after hatching, the insect population’s distribution within the crop canopy, and the volume of foliage ingested by each larva are essential. For example, moths usually do the most damage at the late larval stage. To minimize crop damage from moths, baculovirus needs to be sprayed as early as possible before the insects reach that late stage.

Another biopesticide approach has been to make transgenic plants that manufacture proteins isolated from insect-resistant plant species. Tomatoes naturally make an enzyme inhibitor that deters insects by keeping their digestive enzymes (trypsin and chymotrypsin) from functioning. These inhibitors were isolated by Clarence Ryan at the University of Washington. Ryan transformed tobacco plants with two different forms of inhibitor (inhibitors I and II from tomatoes). The tomato proteins were effectively produced in tobacco and made the transgenic plants resistant to tobacco hornworm larvae.

Biopesticides exist and have been refined for the control of insect pests even though they are not toxic to the insects. These biochemical pesticides include compounds that interfere with insect pheromones (chemicals that attract insects to a potential mate). Their use inhibits insect mating and so the production of the next generation of the particular insect.

Biopesticides are also being implemented to control the population of mosquitoes in some regions of the world that are susceptible to malaria. The idea is that by controlling the mosquito population, the spread of the microorganism responsible for the disease, which occurs when the mosquito takes a blood meal, will be lessened. The strategy has been tested in several malaria-prone countries in Africa.

Biopesticide Resistance

As with chemical pesticides, over time insect populations grow resistant to biopesticides. Bt-resistant moths can now be found around the world. Resistance arises when pesticides are too effective and destroy more than 90 percent of a pest population. The few insects left are often very resistant to the pesticide, breed, and with succeeding generations create large, resistant populations.

Entomologists have suggested strategies for avoiding pesticide-resistant insect populations. One strategy suggests mixing biopesticide-producing and nonproducing plants in the same field, thereby giving the pesticide-susceptible part of the insect population places of refuge. These refuges would allow resistant and nonresistant insects to interbreed, making the overall species less resistant. Other strategies include synthesizing multiple types of Bt toxin in a single plant to increase the toxicity range and reduce resistance, making other biological toxins besides Bt in a single plant, and reducing the overall exposure time of insects to the biopesticides.

Organizations including the US Environmental Protection Agency (EPA) and Department of Agriculture recommend using biopesticides as part of what is termed an “integrated pest management approach” that uses a number of control and crop growth strategies. The aim is to decrease the use of conventional pesticides while maintaining or even increasing crop yield. This approach also helps lessen the development of resistance, since the same biopesticide is not used constantly.

Key terms



Agrobacterium tumefaciens

:

a species of bacteria that is able to transfer genetic information into plant cells





Bacillus thuringiensis
(Bt)
:

a species of bacteria that produces a toxin deadly to caterpillars, moths, beetles, and certain flies




baculovirus

:

a strain of virus that is capable of causing disease in a variety of insects




transformation

:

the process of transferring a foreign gene into an organism





transgenic organism


:

an organism synthesizing a foreign protein, the gene of which was obtained from a different species of organism





Bibliography

Abrol, Dharam P. Integrated Pest Management: Current Concepts and Ecological Perspective. Burlington: Elsevier, 2013. Print.

Copping, Leonard C., ed. The Manual of Biocontrol Agents. 4th ed. Alton: BCPC, 2009. Print.

Copping, Leonard C., and J. J. Menn. “Biopesticides: A Review of Their Action, Applications, and Efficacy.” Pest Management Science 56 (2002): 651–76. Print.

Khan, Mohammad Saghir, A. Zaidi, and J. Musarrat, eds. Microbial Strategies for Crop Improvement. New York: Springer, 2009. Print.

Koul, Opender, and G. S. Dhaliwal, eds. Microbial Biopesticides. New York: Taylor, 2002. Print.

Matthews, Graham, Roy Bateman, and Paul Miller. Pesticide Application Methods. Hoboken: Wiley, 2014. Print.

Panesar, Parmjit S. Biotechnology in Agriculture and Food Processing: Opportunities and Challenges. Hoboken: CRC, 2013. Print.

Reddy, P Parvatha. Recent Advances in Crop Protection. New York: Springer, 2013. Print.

Regnault-Roger, Catherine, Bernard J. R. Philigène, and Charles Vincent, eds. Biopesticides of Plant Origin. Secaucus: Intercept, 2005. Print.

Walters, Dale. Disease Control in Crops: Biological and Environmentally-Friendly Approaches. New York: Wiley, 2009. Print.

How do you critically appreciate a text?

Critical text appreciation is based on the analysis of text from a number of different perspectives. While novices at the art of analysis might think that thinking about the details of a text might make the text boring, in fact, text analysis helps with appreciating a work even more (or, appreciating it in the first place, if the work seems mysterious or boring). 

Context is important, so the first questions to ask include:

• When and where was this text produced?


• How does it relate to texts and other art forms that came before it?


• How does it relate to text/art that came afterwards?


• Who is the author?


• How does the text fit into the author's life?

Beyond that, it is important to look at writing techniques. Here are some questions to think about:

• What genre is the text in? Purpose of text?


• Does the text keep the rules of genre or break them (usually texts do some of both)?


• What are the characteristics of that genre? Given the historical period of the text, what were the characteristics of that genre when the text was written?


• What are literary devices used in the text (imagery, analogy, sounds of words, etc.)?


• How do textual characteristics contribute to the meanings you find in the text? Do they support or undermine them?

You'll find yourself learning a lot about a text through thinking through these questions. The next time you encounter a text like it or perhaps by the same author, you will be able to use what you learned here to understand and appreciate that text better.

By what means and with what success was the slave trade suppressed?

In the 1800s, countries began to ban either the trading of slaves or slavery itself. There were attempts to stop the trading of slaves in the 1800s.

The British used their navy and their government to accomplish this. The British navy would identify the routes that slave traders used. Then, the navy would patrol those routes and seize ships suspected of being involved in the trading of slaves. The British would also attempt to negotiate treaties with countries in order to get them to reduce the trading of slaves. The British also tried to stop the slave trade where the trade was occurring. The British would identify the places where slaves were being traded and station their military at that location.

The United States passed laws banning the trading of slaves. Congress banned international slave trading in the early 1800s. In 1850, slave trading was banned in Washington, DC.

There was some success in reducing the slave trade. Treaties were signed, and ships with slaves were captured. However, slave trading was very profitable, and slave traders didn’t stop trading slaves. Some countries also wouldn’t negotiate treaties with Great Britain to help reduce the trading of slaves. Thus, while slave trading decreased, it didn’t complete disappear until the 1860s.