Fires Role in the Ecosystem Essay Example for Free

Fires Role in the Ecosystem Essay Scientists have studied forests and fires to determine the secret of Natures success in attaining this necessary balance. They have learned that a natural fire results from a certain fuel condition. Some forest types produce and accumulate fuels faster than others; some decompose fuels more readily than others. However, at some point in time, every forest type has fuel of the right quantity and quality for that forest to be ready to burn. In the past, forest fires would benefit the whole forest ecosystem because their frequency and intensity was determined by the systems natural readiness to burn. When there is a departure from the natural fire point, the ultimate, inevitable fire will be more severe. Fed by extraordinary amounts of fuel, a fires intensity may increase beyond the beneficial point for some parts of the ecosystem. Soils can be overheated and root systems damaged. Living tree crowns, as well as dead needles and branches, may be reduced to ashes. The Dilemma Scientists are studying things other than forests and fires things like population increases, wildlife needs, recreation needs and demands, increased hunting pressures, and a diminishing natural resource base. Obviously, all forest fires cannot be permitted to burn uncontrolled according to the whimsical dictates of lightning strikes or the carelessness of humans. Yet, in attempting to protect these forest values, the powerful role of fire has almost disappeared from the ecosystem it once shaped and created. The inevitable release of natural energy is only postponed-the probability of a devastating wildfire is increased. How, then, can the powerful force of fire be used in a way that cooperates, not conflicts, with nature? No Simple Solution Periodic natural fires prevent the heavy buildup of fuel which, when ignited, can harm our forests and ecosystems. Controlling fires in accordance with Natures scheme must be based on fuel management. There is no general prescription or formula for controlling fuels. Forested sites differ, and objectives range from essentially unmanaged wilderness to intensively managed recreation areas. However, in areas where the forest management  objectives require maintaining or reproducing forest or other natural communities natures method fire is a valuable and effective fuel management tool. Fires natural role in reducing fuels is partly replaced in timber-producing areas by the harvest and removal of wood products. However, slash, resulting from these activities, creates another fuel problem. Better use of harvested wood is one answer fire is another. Controlled burning of non useable slash further reduces the fuel load and provides nutrients for the plants and animals that inhabit the area. The technical and scientific refinement of ways to use fire as a management tool has been a major subject of forest research. Scientists are focusing on forest fuel chemistry, fire behavior, meteorology, and other fields to best determine when, where, and how excess fuels are to be burned. Only in the last century has fire in the forest been viewed as a monster. We are now beginning to realize that fire is a natural agent essential for maintaining the natural ecosystems of Florida. Fire is neither all good nor all bad. It is natural. It is powerful. In the proper places, in the right hands, at the right times, fire can be an asset and an ally. To employ fire as a useful friend is much more logical than confronting it as an enemy. Fire is a significant force in the forest environment. Depending upon specific land management objective, plus a host of environmental variables, fire will sometimes be an enemy, at times a friend, and frequently its effects will be mixed between the two extremes. To extend knowledge of fires role in Florida forests, this publication has been developed from scientific literature review and observations by experienced personnel. To be most useful, the general principles that follow must be localized to specific environments or management units in that way, in-depth knowledge of fire can be used to enhance productivity of the earths ecosystems in all their infinite variety. One great truth of this environmental age is that it is far better to complement natural systems than to manipulate them for single-purpose gain. It is through recognition of ecological interrelationships that we can best manage natural resources for the public good. Ignorance of ecological interrelationships is no excuse for land management errors. To meet future  environmental demands, land managers must build uncommon strength in all three fire activities: prevention, protection, and fire prescribed for ecological benefits. Fire management, in full partnership with other environmental factors, is necessary for quality land management. The Two Faces of Fire The Monster Uncontrolled wildfire raging through a forest can have disastrous effects. Healthy trees are reduced to blackened snags; shrubs that provided food and cover for wildfire become ashes; under the intense heat some soil nutrients are vaporized and become airborne in clouds of choking smoke. Ash falls on rooftops, window sills, and darkens clothes drying outdoors in nearby towns. Where people once enjoyed a green, scenic landscape, they see a stark, gray landscape. A forest has been grossly changed; the web of life it encompassed and nurtured has been broken. Here, fire has shown its mastery over the land and has behaved as a monster. The Friend Think about fire for a moment. If you have warmed your hands in its welcomed heat and enjoyed its friendly light, you know that all fire is not the raging holocaust. Fire, along with air, water, and earth, is a basic environmental factor. We do not judge air as bad because of periodic, destructive hurricanes. We are drawn to water rather than avoiding it despite its potential to cause devastating floods. We do not fear the earth though we know that forces beyond our control can cause it to quake and slide. Fire, no less than air and water, has been a natural directing force in human evolution and the earth we inhabit. History indicates that humans learned to use and control fire. Fire was, perhaps, our first tool. Yet today the acceptance of fire in the forest seems basically contrary to our beliefs in modern times. Perhaps we feel we have progressed beyond the need for direct dependence on this natural force. Or maybe we simply do not know and understand it any longer. Lightning In the Making Continued sunny and warm except for isolated afternoon or evening thunderstorms. Thirty percent chance of rain. This is a familiar midsummer  weather forecast in Florida. From over the Atlantic Ocean and the Gulf of Mexico, air   masses directly affect Floridas weather. Warm air is lifted high into cool, upper air layers. The cooling of this rising air causes its moisture to condense and clouds to form. Moisture droplets form in the upper; cold parts of the clouds. When they reach a certain size, the droplets begin to fall earthward, away from the influence of the cold air back into warm, uplifting currents. The droplets may again vaporize and be lifted even higher into the upper air layers. A repeated cycle of warming, lifting, and cooling causes the buildup of tall columns of billowy clouds. The bases of the clouds may be 3,000 feet above sea level the tops of the cloud columns develop upward to levels of 60,000 feet. The Ignition Source Inside the clouds electrical charges build up and separate into positive and negative centers. The upper portion of the cloud becomes positively charged and the lower portion becomes negatively charged. The negative charge near the cloud base induces a positive charge on the ground a reversal of the fair weather pattern when the ground charge is negative. Potential gradients between positive and negative centers, with some assistance from friction caused by falling water droplets, lead to those large sparks known as lightning discharges. Cloud-to-ground lightning is usually a discharge between the negative lower portion of the cloud and the positive charge on the ground. Most thunderstorms in Florida are accompanied by rain. Lightning fires occur when the lightning bolt strikes outside the area of rainfall or it ignites dry fuels that smolder through the rain shower and begin to burn as the area dries out following the shower. Energy to Use or Burn From a distance, pines and other vegetation look fresh and green. Close inspection reveals that the greenness is a shell enveloping a core of dry needles, twigs, and branches. In the needled or leafy part of the tree, known as the crown, growth occurs at the branch tips, so the youngest, greenest parts are always around the outside edges. Here, photosynthesis occurs. Photosynthesis is the major function of every green plant. It is the process by which light energy from the sun is converted to a form of energy that can be stored and used by the plant. Generally, the conversion is to  chemical energy and involves the formation of a series of complex organic compounds. Some of the compounds impart the piney odors we enjoy in forests. What we cannot tell from their pleasant aroma is that these compounds are very flammable. Once stored, the energy can be used in different ways. For example, it can be used by the plant to produce wood or grow more needles in which more energy conversion will take place. It can be used as a source of food by animals that browse the leaves and twigs where the compounds are stored. The energy can also be used to produce seed to germinate and produce another plant. This energy storing process takes place with shrubs and grasses as well as trees; photosynthesis and the energy conversions and transfers that occur are complex, but the result is clear enough: during one growing season in one acre of forest, enough sun energy is converted and stored in plant material to equal the energy reservoir in 300 gallons of gasoline. Fire and the Forest We often regard fire as an agent of destruction, but to Nature, it is an agent of necessary change. Fire changes one form of energy to another. Green plants change light energy to chemical energy, fire changes chemical energy to heat energy. Fire breaks down complex organic molecules to smaller ones the same thing that occurs when we digest food. The protein in a piece of meat cannot be used directly by the human body to build cells and tissues. We must eat the meat before large protein molecules can be broken down to smaller amino acid molecules, recycled through our bodies, and rebuilt into human tissue. When a fire changes a log to ash, nutrients bound in chemical compounds are released and changed to a form that is more water soluble. In this soluble form, nutrients percolating into the soil are again usable in the growth of other plants. Fire also effects a more visible change. Ash and nutrients occupy less space than trees and shrubs. By creating openings in forests, fire changes space relationships. Species that remain in these openings may be fire tolerant. Other species that cannot withstand fire are eliminated. Thus, fire changes both the composition and the density of the forest. This change will remain for several years and affect the fuels available during the next burning cycle. Scientists who study plant and  animal relationships tell us that forests in this part of the country owe their existence and continued presence to a long history of periodic fires. This association of some tree and shrub species with fire is an example of adaptation. Forests in Florida have existed here for at least 12,000 years. During that time, thousands of fires occurred annually. Plant species that survived these fires did so because of special features or characteristics they possessed. Plant species lacking these features were eliminated from frequently burned areas; their distribution has been confined to areas where fires are less likely to occur, moist areas such as bays, swamps, and creek bottoms. Fires, like many natural events, are somewhat cyclic. The cycle is governed by conditions such as general climate, topography, soil type, existing vegetation, and other factors. Accordingly, the repeatability of the cycle varies. Before 1900, fire-susceptible areas probably had fires every 3 to 10 years. In areas less likely to burn, the cycle may repeat every 10 to 100 years. Cyclic, recurrent fires of the past 12,000 years were important agents of selection in determining plant species and distribution in Florida. Trees Born of Fire Special adaptive features have allowed some plants to survive naturally occurring fire. Adult southern pines have a thick bark that insulates the inner, living tissues from fires heat. Longleaf pine is so fire resistant that some trees almost always escape fires injurious effects. These trees become seed trees for the reforestation of a burned area. Sand pine exhibits yet another adaptation for coping with fire. Sand pine cones remain closed until a fires intense heat opens the cone and allows the seeds to fall out. Seeds of cone-bearing trees that persist in fire-susceptible areas sprout and grow best under conditions created by fire: soil free from litter, an increased nutrient reserve, plus open areas with plenty of sunlight. In contrast, species less adapted to fire, such as oaks, gums, cypress, and cedar do not usually reseed a burned area directly. Seedlings of these species prefer partial shade and plenty of moisture. Generally, they will reestablish only after some other type vegetation is present. The Changing Natural fires keep Floridas forests dynamic, diverse, and beautiful. Florida was named by the early explorers because of the abundance of wildflowers in  areas kept open by frequent fires. Historically, timber stands were replaced by young trees; sometimes one type of forest was replaced by another. Changes in tree cover occur together with even more encompassing changes because a forest is more than just trees. A forest displays interdependence, interrelationships, and competition among trees, shrubs, flowers, grasses, big and little animals, soils, microbes, minerals and nutrients in soils, and the air pervading and surrounding all of these. A forest is a complex life system. Each part has a place and a function in its organization an organization called the forest ecosystem. Because all parts of the system are interrelated, no one part can change without a widespread effect throughout the entire system. Forest fires affect more than trees. Fire-caused changes in ecosystems result in both stress and relief to plant and animal life both to individuals and to whole plant and animal communities. Thousands of years of natural fires achieved a dynamic balance between the stresses and relief. The fire-adapted pine forests thrived over vast areas. They provided habitat for hundreds of species of grasses and wildflowers, as well as dozens of animal species. All these species would quickly begin to decline in number and health and eventually disappear completely if fire is excluded. Fires Role in the Ecosystem A Balancing Act Scientists have studied forests and fires to determine the secret of Natures success in attaining this necessary balance. They have learned that a natural fire results from a certain fuel condition. Some forest types produce and accumulate fuels faster than others; some decompose fuels more readily than others. However, at some point in time, every forest type has fuel of the right quantity and quality for that forest to be ready to burn. In the past, forest fires would benefit the whole forest ecosystem because their frequency and intensity was determined by the systems natural readiness to burn. When there is a departure from the natural fire point, the ultimate, inevitable fire will be more severe. Fed by extraordinary amounts of fuel, a fires intensity may increase beyond the beneficial point for some parts of the ecosystem. Soils can be overheated and root systems damaged. Living tree crowns, as well as dead needles and branches, may be reduced to ashes. The Dilemma Scientists are studying things other than forests and fires things like population increases, wildlife needs, recreation needs and demands, increased hunting pressures, and a diminishing natural resource base. Obviously, all forest fires cannot be permitted to burn uncontrolled according to the whimsical dictates of lightning strikes or the carelessness of humans. Yet, in attempting to protect these forest values, the powerful role of fire has almost disappeared from the ecosystem it once shaped and created. The inevitable release of natural energy is only postponed-the probability of a devastating wildfire is increased. How, then, can the powerful force of fire be used in a way that cooperates, not conflicts, with nature? No Simple Solution Periodic natural fires prevent the heavy buildup of fuel which, when ignited, can harm our forests and ecosystems. Controlling fires in accordance with Natures scheme must be based on fuel management. There is no general prescription or formula for controlling fuels. Forested sites differ, and objectives range from essentially unmanaged wilderness to intensively managed recreation areas. However, in areas where the forest management objectives require maintaining or reproducing forest or other natural communities natures method fire is a valuable and effective fuel management tool. Fires natural role in reducing fuels is partly replaced in timber-producing areas by the harvest and removal of wood products. However, slash, resulting from these activities, creates another fuel problem. Better use of harvested wood is one answer fire is another. Controlled burning of non useable slash further reduces the fuel load and provides nutrients for the plants and animals that inhabit the area. The technical and scientific refinement of ways to use fire as a management tool has been a major subject of forest research. Scientists are focusing on forest fuel chemistry, fire behavior, meteorology, and other fields to best determine when, where, and how excess fuels are to be burned. Only in the last century has fire in the forest been viewed as a monster. We are now beginning to realize that fire is a natural agent essential for maintaining the natural ecosystems of Florida. Fire is  neither all good nor all bad. It is natural. It is powerful. In the proper places, in the right hands, at the right times, fire can be an asset and an ally. To employ fire as a useful friend is much more logical than confronting it as an enemy.

truama c-spine Essays -- essays research papers

Trauma C-Spine   Ã‚  Ã‚  Ã‚  Ã‚  This essay is not intended to criticize any emergency medical or hospital staff. I am writing this essay out of concern for patients who come into the emergency room that may have a jeopardized spinal cord resulting from an injury or suspected injury to their cervical spine. I am a certified emergency medical technician, farm-medic instructor and currently a medical diagnostic student doing clinicial's. In the United States each year there are approximately 10,000 reported cervical spine injuries that come into emergency rooms. Motor vehicle accidents account for approximately 45%, falls approximately 30%, the remaining 25% from sports and miscellaneous. Although only a small amount of these spinal injuries are life threatening, they all need to be treated as such. Survival of these patients depends on pre-hospital care, emergency room care and quality diagnostic radiographs, all done at times under extreme time restraints and pressure.   Ã‚  Ã‚  Ã‚  Ã‚  The number one goal in patient care is not to make any situation worse than it already is. Most pre-hospital care is usually done by emergency medical technicians. Their main concern is to assess, stabilize and transport the patient to a facility that can give additional care and treatment. The emergency room staff is the second step to the patient’s survival. Their duties include further stabilization, evaluation and treatment of the patients’ injuries. Radiographers are to supply ER doctors with quality diagnostic X-rays so they can make informed decisions about further patient care. Each of these groups need to be aware of what is involved with the other’s job, so that the patient will receive the best of care.   Ã‚  Ã‚  Ã‚  Ã‚  Emergency medical personnel are trained in the proper pre-hospital care of patients in the field. Pre-hospital care of patients suffering from suspected cervical spine injury involves making sure the patient has a patent airway. Placing a properly sized C-collar on the patient to stabilize the neck. Packaging the patient for transport to the emergency room, which involves proper placement and securing of patient on backboard, and making sure to secure the head and shoulders so there is no movement of these areas by the patient. While enroute to the hospital emergency room further assessment of patient can b... ...this! EMS responds to a motor vehicle accident and have to place a patient on backboard with a c-collar applied. The EMS crew just had a continuing education program presented by an X-ray technician that showed them what they could do to help speed up c-spine exam time and also help reduce patient risk, so the EMS crew removed the patients jewelry before they applied the c-collar. Upon arrival at the hospital the proper X-rays were ordered to evaluate the patient for cervical spine injury. The radiographer arrived with help to do the necessary exam. The patient was taken into the exam room and since the radiographers had just completed a continuing education program on patient care, where cervical spine injuries were involved, they were very careful when moving the patient. They kept the patient on the backboard and did not attempt to move the patient’s head or neck. The radiographers made sure that the films they showed to the doctors were of diagnostic quality.   Ã‚  Ã‚  Ã‚  Ã‚  Could this happen? Yes, if everyone involved was properly trained, took pride in their work and departments were adequately staffed.   Ã‚  Ã‚  Ã‚  Ã‚  Does this happen? I hope so.

Case Review Law of Tort

TRESPASS TO LAND BUKIT LENANG DEVELOPMENT SDN BHD v. TELEKOM MALAYSIA BHD & ORS [2012] 1 CLJ FACTS The plaintiff purchased a land from Oakfield Enterprises Sdn Bhd through a sale and purchase agreement dated 15 May 1996. The plaintiff was aware at that time of the presence of squatters on the land. Following the said purchase, the plaintiff commenced eviction proceedings against the squatters and succeeded in obtaining judgment where the court ordered that the squatters surrender vacant possession of the subject land to plaintiff.The plaintiff’s solicitors demanded that second defendant cease supply of electricity and remove all structures in connection with the supply by letter dated 28 April 2004. Plaintiff brings a suit due to second defendant’s refusal to comply with the demand. The defence counsel, however, argued that second defendant could not be held liable for trespass in view of its statutory obligation under the Electricity Supply Act 1990 (ESA), and the plai ntiff had failed to distinguish between the lots owned by the plaintiff and the rest of the land.ISSUES 1. Whether second defendant's failure to comply with plaintiff's demand to cease supply of electricity and remove structures in plaintiff's land can be amounted to trespass to land? 2. Whether second defendant liable for trespass to a certain extent? JUDGMENT 1. The High Court had come to a conclusion that the second defendant liable for trespass to the extent of supplying electricity to legal occupants in plaintiff's land.The illegal occupants did not have the authority to allow TNB as licensee to place any structures on the land of its cables or wires to run over the plaintiff’s lots which would be trespass. A valid and subsisting High Court order declaring the occupants’ status as squatters or trespassers had been served on second defendant and they had to comply with the plaintiff’s demand to cease supply of electricity premised on a valid and enforceable order.Second defendant as a public utility provider had failed to discontinue the trespass when due notice of illegal occupation had been given. 2. Plaintiff had vide its solicitors’ letter of 28 April 2004 put second defendant to notice that the court had determined that the occupiers on the plaintiff's land who had been supplied electricity were trespassers and the lot numbers owned by the plaintiff were supplied. The defence raised there was no evidence of any response from second to the effect that the plaintiff’s lots could not be identified from the entire piece of land.The occupants being squatters were strangers to the plaintiff whereas second defendant was in possession of records showing their identities and location of the households that had electricity supply. Hence, the issue of non-identification or demarcation of the plaintiff’s lots did not arise in this case. 3. So, second defendant were held liable for trespassing plaintiff's land by placing c ables and wires to run over plaintiff's lots and also by supplying electricity to illegal occupants in plaintiff's land.COMMENTARY I agree on behalf of High Court's decision where second defendant (Telekom Malaysia Bhd) should be liable for trespassing into plaintiff's (Bukit Lenang Development Sdn Bhd). This is because they had been informed earlier by plaintiff's solicitor to cease supply of electricity and remove all structures in connection with the supply by letter dated 28 April 2004 but they still failed to do so. They also know that the people they are supplying the electricity are illegal occupants of plaintiff's land.From a legal view, even by placing something on other's land and continue the act would be considered as trespass to land. So, second defendant had trespass plaintiff's land intentionally as they were informed earlier to comply with it. Furthermore, second defendant's action of supplying electricity to the illegal occupants is regarded as immoral by abetting a nd conspires with them to occupy plaintiff's land illegally. Therefore, in moral view, they should avoid from doing so. In conclusion, High Court's decision that second defendant liable for trespassing plaintiff's land is reasonable.PASSING OFF DANONE BISCUITS MANUFACTURING (M) SDN BHD V. HWA TAI INDUSTRIES BHD [2010] 8 MLJ 500 FACTS In early April 2001, the Plaintiff discovered that the defendant, Hwa Tai Industries Bhd, had been manufacturing and selling chocolate chip cookies bearing the trademark â€Å"Chipsplus†. The plaintiff subsequently requested that the defendant cease the manufacture and sale of cookies bearing this trademark, on the basis that the trademark, as well as get-up and packaging of the product, were confusingly similar to their registered â€Å"ChipsMore† mark.However, the defendant refused to do so, and as such, the plaintiff sued the defendant for trademark infringement and passing off. The plaintiff argued that the defendant’s â€Å"Ch ipsplus† trademark infringed upon its registered trademark, while the similar get-up and packaging of the cookies amounted to the defendant passing off its â€Å"Chipsplus† cookies as the Plaintiff’s â€Å"ChipsMore† cookies, and this affected their business, reputation and goodwill in Malaysia.The defendant however denied the plaintiff’s claims, and further contended that the â€Å"ChipsMore† registration had lapsed, and was therefore invalid. ISSUES 1. Whether Hwa Tai Industries Bhd is liable for passing off defendant's chocolate chip cookies â€Å"ChipsMore† trademark? JUDGMENT 1. It was held that the defendant’s mark â€Å"CHIPSPLUS† used on chocolate chip cookies were to bring result in confusion to the public as the mark â€Å"CHIPSPLUS† and the Plaintiff’s registered mark for â€Å"CHIPSMORE† for the same product are conceptually similar.The court found that the defendant was liable for infring ement because the plaintiff had a registration certificate and renewal certificate evidencing a valid trademark, and the Plaintiff had not given the defendant permission to use their trademark. Furthermore, as â€Å"Chipsplus† was similar to â€Å"ChipsMore†, there was a possibility of confusion or deception amongst the public. Court found in the plaintiff’s favour and allowed the plaintiff’s claim for infringement and passing off. COMMENTARYI am against the decision made by the court as the mark ‘CHIPSPLUS' used by defendant was like merely to use the word ‘CHIPSPLUS' to promote their new cookies products with extra and additional chips and it is not necessary to prove that the word ‘CHIPSPLUS' can be used by plaintiff only. Other manufacturers can have freedom to use any appropriate word as label for their products as long as it does not totally imitate other manufacturer's product label. Plaintiff maybe has the idea to promote their c hips cookies by using the ‘CHIPSPLUS' word too and not have the intention to pass off defendant's trademark.

Sino-Cuban Fallouts and Make-Ups - 1568 Words

Chinese ties to the Cuban communist party, the People’s Socialist Party (PSP), date back to 1949, which is before Fidel Castro came to power. Sino-Cuban relations between 1959 and 1989 can be described as inconsistent at best, with a number of changes in attitude on the part of Castro towards Chinese leaders. It is considered one of the great ironies of history that although Castro publicly condemned Mao â€Å"with a viciousness rarely encountered in modern international relations,† the Cuban leader was more like his Chinese counterpart than any other communist leader. (Ratliff, 206) They had a number of similarities, including the use of personality cults, shared positions on domestic development and international affairs, and similar†¦show more content†¦Essentially, the Soviet Union and the Chinese communists were in support of two completely different ideologies, and Castro chose to align himself with the Soviets, knowing he would alienate the Chinese in th e process. From that point on, the Sino-Cuban dispute resulted in â€Å"hostility between the two governments,† which was a direct result of the conflict between the Soviet Union and the People’s Republic of China, and a dispute â€Å"over the strategy of guerilla warfare.† (Ratliff, 210) Diplomatic relations completely disintegrated in 1966 at the Afro-Asian-Latin American People’s Solidarity Conference in Havana. During this conference Castro accused Mao of â€Å"confusing Marxism-Leninism with fascism.† (Ratliff, 210) Castro also accused the Chinese government of â€Å"criminal economic aggression† for cutting back its rice shipments to Cuba. (Ratliff, 210) Castro even brought these attacks to a personal level, suggesting that â€Å"Mao was a senile old man,† who, in spite of having done some good things early in his career, had committed a number of atrocities toward the end of his life. (Ratliff, 210) The conflict, since titled the â€Å"rice war,† between China and Cuba consists of four phases. Firstly, Cuba is the only Latin American country with rice as a staple in its diet. Up until Castro came to power in 1959,Show MoreRelatedOne Significant Change That Has Occurred in the World Between 1900 and 2005. Explain the Impact This Change Has Made on Our Lives and Why It Is an Important Change.163893 Words   |  656 Pagesstrands of global history in the twentieth century has often led to its neglect. The fact that the most recent phase of the human experience is usually covered only at the end of a multiterm sequence of world history units has meant that it often ends up becoming a rushed add-on of rather random, abbreviated capsule summaries and general overviews. In view of the fact that no phase of history can begin to match the twentieth century in terms of the extent to which it has shaped the contemporary world