What Impact did Brown v. Board of Education Supreme Court case have on Coursework

What Impact did Brown v. Board of Education Supreme Court case have on the reduction of racial discrimination in America - Coursework Example ideration of the rights of every American citizen thereby overturning the discriminative legislations that existed in the country’s education system before as the discussion below portrays. The Supreme Court ruling declared that other previous laws that informed the institution of separate schools for both black and white communities null and void. Apparently, American laws sustained discrimination in every sector of the economy with the country’s education system having systematic laws banning the integration of the two communities. An 1879 Kansas law permitted the creation and operation of separate elementary schools among other educational facilities for both the whites and the blacks1. The law however did not restrict the formation and composition of the schools. This portrayed the state’s recognition of the discriminative social structure thus the creation of equally discriminative social structures. In the ruling, the Warren court made a unanimous ruling overturning such laws by stating "separate educational facilities are inherently unequal†. The ruling was fundamental since it determined that the de jure  racial segregation  was a violat ion of the Equal Protection Clause  in the country’s Fourteenth constitutional amendment. The ruling was a major success to most of the civil rights activists and the abolitionist campaigners thereby setting stage for integration of communities in the country. The plaintiffs in the case were a group of thirteen parents who instituted the case against the Board of Education in Topeka, Kansas. The parents represented twenty children who experienced various instances of racial discrimination in the city. Oliver Brown joined the case thereby becoming the main plaintiff in the case after deliberation with the other thirteen parents. Apparently, Brown’s daughter Linda studied at Monroe Elementary school situated about two kilometer away2. The young girl would walk for more than six blocks before boarding a bus to

Acheulean technology Essay Example for Free

Acheulean technology Essay The Oldowan technology is referred to as Mode 1, preceding the Mode 2 Acheulean technology. The latter implies that it is more advanced and more sophisticated than the former. Mode 1 technology only refers to simple hand tools which include choppers, scrapers, awls and woodworking tools. On the other hand, Mode 2 technology was the â€Å"retouched† and reworked Mode 1 tools. This ensures that their tools were more symmetrical making it effective and useful for its purpose It has been an argument on whether the ergaster was to be considered as a different taxon since some researchers claim that they feature â€Å"different† characteristics from other Homo taxons and also associates them as the direct ancestor of humans. KNM-ER 3733 and KNM-ER 992 are some ergaster specimen that were found. These specimens show no significant difference from other homo taxon to qualify it as a new species. Researchers still support Homo erectus as the closer ancestor of modern humans and that the ergaster are â€Å"H. erectus from Africa† The Turkana Boy was a significant find since it provides evidences of evolution of humans. By studying its morphology, scientists found out that the Turkana boy exhibits the possibility of having its own language and also how modern humans evolved traits from it. Bipedalism, brain volume, size of canines and inner ear bones are some features shared by Australopithecus and Homo sp. This suggests that they share a common ancestor. Works Cited http://www. archaeologyinfo. com/homoergaster. htm http://www. crystalinks. com/turkanaboy. html http://www. ecotao. com/holism/hu_austral. htm http://www. crystalinks. com/Oldowan. html

Hhv-8 :: essays research papers

â€Å"Human Herpes Virus-8 (HHV-8) and Kaposi’s Sarcoma (KS)†   Ã‚  Ã‚  Ã‚  Ã‚  Human herpes virus (HHV-8) poses a challenging task for researchers determining its role in Kaposi’s sarcoma (KS). People with KS are distinguished by their placement in four categories. The first category consists of elderly males of Mediterranean or Eastern European Jewish descent. The second category consists of individuals of all ages from Africa. Neither one of these categories is associated with immune deficiency or known environmental factors. The last two categories are associated with organ transplants or HIV-1. In all forms of KS males are predominantly affected.   Ã‚  Ã‚  Ã‚  Ã‚  Kaposi’s Sarcomas are known to harbor cells known as spindle shaped cells (SC). The spindle shaped cells are associated with abnormal blood vessel development and blood leakage. Although, the SC is the most frequently encountered cell in KS tumors it is undetermined if they are neoplastic cells or hyperproliferating cells or an altered cell induced by cytokines (INF-).   Ã‚  Ã‚  Ã‚  Ã‚  Although, it is easy to believe that all cells in a tumor are neoplastic, evidence suggests otherwise. There are three characteristics that are present in all KS cells whether they are neoplastic or not. The first is absence of a histologically distinguishable neoplastic cell. The second is the lack of usual chromosomal abnormalities. The last is a combination of three features angiogenesis, inflammation, and proliferation.   Ã‚  Ã‚  Ã‚  Ã‚  The one factor that brings the four categories of people infected with KS is HHV-8 found in KS tissues. Although, HHV-8 is thought to be connected to KS, HHV-8 itself has very low risk factor for KS development. Most reports on KS indicate a 2% to 10% prevalence of HHV-8 in the world, but in the U.S. there is thought to be a 5% prevalence among men according to a 1970s baseline incidence of KS. In relation to HIV-1 incidence of KS increases by a factor of 20,000 to 50,000 times with the presence of HHV-8.   Ã‚  Ã‚  Ã‚  Ã‚  It is postulated that HIV-1 infections promote HHV-8 replication indirectly by suppression of host immune systems. KS is thought to begin with micro-vascular lesions mediated by different environmental factors for each of the four categories of KS. One of these factors is abnormal cytokine production; in HIV-1 associated KS, this includes an increase in inflammatory cytokines, such as IFN , TNF , and IL-7 that are enhanced by Tat of HIV-1. Tat which is essential for HIV-1 replication is released and taken up by other cells, where it inhibits T-cell proliferation and promotes abnormal cytokine production, adhesion, and growth.

Taiwan :: History

Taiwan For centuries, Taiwan has been ruled by alien regimes. Modern Taiwanese history is a chronicle of the Taiwanese' struggles against oppression and fight for independent survival. Since 1945, Taiwan under the Kuomintang (KMT) regime has been subject to the threat of China's invasion. Even though recently the tensions across the Straits of Taiwan has loosened gradually, to Taiwanese, the unification policy stressed by both the KMT regime and the Chinese government still poses a grave danger of a forced and forcible merger with China. On August 31, 1993, the People's Republic of China issued a document titled, "The Taiwan Question and the Reunification of China." Circulating in seven languages, this diplomatic white paper manifested its intent and ambition of annexing Taiwan through its distortion of history, misconstruction of international law and treaties, and disregard for the will and welfare of the Taiwanese. Though less dogmatic and more pragmatic than before, the KMT's response remains ambiguous and problematic: the KMT still insists that the Communist regime cannot legitimately represent China, while emphasizing its own capability of resolving this "Chinese problem" eventually. Under such circumstances, we think it necessary to explicate our point of view from the perspective of the Taiwanese. China released a paper that states that "Peaceful Unification" and "One Country, Two Systems" are the basic principles of its Taiwan policy. The paper lists four guidelines: one China, coexistence of two systems, extensive autonomy, and peaceful negotiation. China warns that the Taiwan question is a purely domestic issue and thus to be solved under the premise of "One China." It further pronounces that peaceful unification is a fixed policy of the Chinese government. However, this government will reserve the right to take all action necessary, including military action, to protect its territorial integrity and governing authority. As a note directed at foreign states, the paper delivers its intention to keep out foreign intervention. "The Chinese government is not obliged to any foreign country and makes no promise whatsoever." In our opinion, the Chinese assumption and interpretation of the Taiwan issue are extremely absurd. Taiwan by no means is a part of the People's Republic of China, whether from the perspective of history, international law, or reality. This being the case, what position does the PRC have to formulate the "peaceful unification, one China" policy which aims at devouring Taiwan? China's chauvinistic ambitions are clearly manifested in light of this.

Hr on Organizational Essay

Discuss the impact of HR on organizational effectiveness (if possible, include examples from where your work. ) The human resources department of an organization if very important to the effectiveness of the organization due to the fact that it is the â€Å"core† of the organization. It helps a company operate smoothly and effectively by providing assistance, assurance, and confidence. The human resources department at my work not only keeps track of our payroll, time clock, etc. They also keep up to date with the laws and regulations of the company and legal aspects of things. How do the HR policies for an MNC(multinational corporation) differ from those of a company operating exclusively in one country. Give examples. A multinational corporation (MNC) is a firm that is based in one country and produces goods or provides services in one or more foreign countries. HR policies for a MNC differ from those of a company operating in Just one country for numerous reasons. The MNC must take into account language, culture, ethics, gestures, laws, regulations, customs, economy, and politics of not Just the home country but the host country as well. For example, Coke sells their product all over the world. They must change their marketing to accommodate the Chinese. The language must be changed, and even the recipe must be altered. The HR policies must follow the different rules, regulations, and cultures of the different countries they are doing business in. Question 1: Discuss the impact of HR on organizational effectiveness (if possible, include examples from where you work). HR has is very important effect on an organization’s effectiveness. An employee’s culture, if it is passionate and intelligent, an improve a company’s success because it gives the highest quality of ideas to help the company. HR’S main focus is to use individuals to achieve organizational objectives. Effective HR requires great management and all managers get things done through the efforts of others. Individuals within an organization are indeed a major part of the culture of the company. Question 2: How do the HR policies for an MNC (Multinational Corporation) differ from those of a company operating exclusively in one country? Give examples. HR policies for MNC (Multinational Corporation) are iffering from those of a company operating exclusively in one country because they have to protect their product with the best of their ability. Some company’s products could vary from country to country. Keeping their identity should be very important for a company. They also might have to promote differently along with changing names to fit the suppliers. Companies operating in one country usually don’t have to chance anything for the people to buy it. The organization doesn’t have to worry about their identity being change because most of the people that are buying the product are from the same origin.

Francois Marie Arouet (Voltaire)

Francois Marie Arouet (Voltaire) Francois Marie Arouet (Voltaire) was a French philosopher and a writer. Voltaire was born in the year 1694 in Paris. As a young boy, Voltaire received his education at the Jesuit school between the years 1704 and 1711. At the school, Voltaire learned Latin, Greek, English, and Spanish.Advertising We will write a custom essay sample on Francois Marie Arouet (Voltaire) specifically for you for only $16.05 $11/page Learn More Between the years 1711 and 1713, Voltaire studied law while working as a secretary in Paris. Later on, Voltaire quitted the law school, and concentrated on writing contrary to his father’s wishes. As a writer, he wrote several writings in all major literary fields. It is estimated that he wrote more than 1800 books, 20 000 letters and numerous brochures. Through his works, Voltaire became prominent for his wit and hilarious verses. During the Voltaire’s time, Europe was going through the age of enlightenment. With contributio n from various intellectuals, advance knowledge spread across most urban areas in Europe. In spite of the advanced knowledge, it should be noted that stern and suppressive laws with severe consequences were practiced at the time. Similarly, it was blasphemous to champion Christian dogmas. In spite of this, Voltaire became a social reformist, and criticized religious intolerance, war, and social injustices in French institutions. As a result, Voltaire was arrested severally and imprisoned by the authorities. To date, Voltaire works are considered absurd. His works portray him as a racist individual, who has no respect for the Jews and the Africans. More often, he questions the Africans’ intellectual ability due to their involvement in the slave trade. Until his death, at the age of 83, Voltaire worked as a writer. In writings, satire refers to the art of using irony, mockery and sarcasm to provoke individuals’ or society’s behaviors. For a writing to be acknowled ged as a satire, it must possess the following five characteristics: be targeted at the crooked, be humorous, be reform oriented, be ironic, and be exaggerated. Satirical writings try to point out faults in society and organizations. By doing so, actions, injustices, shortcomings, and policies are denounced. Most writers do not choose to express their thoughts through satire to cause harm or damage, but rather to expose the vices in the society through humorous and comical ways. As a result, appropriate use of satire is considered as the most effective way of exposing evil traits in the society. In my opinion, Voltaire through Candide uses satire to condemn the world’s evil, Christian dogmas, and war in the society he lived in. Candide ridicules a variety of secular and idealistic theories. He sarcastically illustrates several inherent evils in the world such as earthquakes, diseases, and storms. Through this text, religious leaders and the authorities felt offended.Advertisi ng Looking for essay on literature languages? Let's see if we can help you! Get your first paper with 15% OFF Learn More

Analysis of The Catch by Stanley Kunitz

Analysis of The Catch by Stanley Kunitz The lesson being taught in this poem is that there is a price for everything we have, and knowledge cannot be captured in a "bottle". The dragonfly is described in the poem as this little delicate creation which is very maneuverable and acrobatic. Less image than thought is saying the dragonfly has very little to show on top where things are obvious, this is an effective simile because people tend to think of bugs as having a very small brains. The dragonfly later on becomes the victim of the father. The child would not suspect that something as little and innocent looking can actually have a catch to it. The dragonfly is being compared to a hidden price is a very effective simile because it can disguise it self and not be found until it is too late. The poem also says "Swoosh went the net with a practiced hand" and the author implies that the father is an experienced man who already ran into something that had a catch to it, he is trying to use the bug as an example to his son to te ach him what he learned the hard way.Powdered milkThe dragonfly is killed when it's captured and that shows how you can kill knowledge when you try to capture it. Killing the knowledge when trying to collect it is the whole catch to it. I can relate to the lesson taught in this poem. I can think of a lot of times when my parents talked to me about something but later that week I'd go and do the exact opposite. For example every winter my mom told me to wear my jacket but I'd just run off outside without it and every winter I would get sick, now that I grew up a...

Hiral Patel Essays (317 words) - Free Essays, Term Papers

Hiral Patel Essays (317 words) - Free Essays, Term Papers Hiral Patel BA 2196 Section 703/Paul A. Evangelista Writing Assignment: Crisis Communication Part II Carnival managed its crisis appropriately when it used social media as a megaphone to provide information of the passengers and the crisis. For example, Carnival created a page on the official cruise website for news updates. It also updated its Facebook page, and two Twitter feeds to provide more information about the situation. Writer Rich Thomaselli speaks of Carnival's social media actions, saying "[Carnival] is also using two Twitter feeds to issue updates, such as We've taken more than 7,000 calls from family and friends and have been in regular contact with our guests' designated on-shore contacts" (Thomaselli, 2013). Carnival's action showed its caring about its passengers and was willing to do anything to get them back home and safe. Families back home worried about their loved ones and wanted as much information as possible. Thomaselli provided further details on fixed reimbursements such as "[Carnival] offering every passenger $500, a flight back home, a full refund on the ir booking on the Triumph," (Thomaselli, 2013). Carnival relayed all responses through social media to show their dedication. Timothy Coombs would advise for this reaction as he states, "the news media are drawn to crises and are a useful way to reach a wide array of publics quickly" (Coombs, 2007). Carnival's usage of social media to provide updates on the situation thus served to intensify the commitment of Carnival to take care of its customers. In this way, Carnival's decision to use social media throughout the crisis made the public aware of what was going on. References Coombs, W. T. (2007, October 30). Crisis Management and Communications. Retrieved from instituteforpr.org/topics/crisis-management-and-communications/ Thomaselli, R. (2013, February 14). Carnival Doesn't Shy Away From Triumph Crisis But Is Damage Done? Retrieved April 04, 2017, from http://adage.com/article/news/carnival-cruises-pr-response-triumph-crisis/239819/

The war in syria and its consequences on lebanon Research Paper

The war in syria and its consequences on lebanon - Research Paper Example lion attacks during the war hence making it further impossible for the people in Syria to access basic amenities like school and hospitals (White, 15). At the same time, the warring parties assaulted civilians by using mass weapons for destruction like chemical guess. Following that, there have been a great number of Syrians moving out of the country to Iraq, Jordan, Turkey, Egypt and Lebanon. Lebanon became home to a large number of refugees from Syria owing to the fact that it has the longest border with Syria. Following that, Lebanon has been an integral player as a consequence of the dynamics of the war in Syria (Barnes-Dacey, 15). This paper will tackle the issues that have arisen following the upsurge of refugees in the Lebanon borders and Lebanon as a country. At the same time, the paper will tackle various aspects in relation to the effect of the Syria’s civil war on Lebanon. Government instability following divided support of the war in Syria, which has been instigated by the fact that in the top leadership of the Lebanon, both pro - al Assad and pro - rebel groups do exist. The part will involve a brief information on the war in Syria siting its effects and causes. At the same time, the section will shade light on the role of Lebanon in the war, bringing out the reason as to why it plays an integral role in the Syrian war. In addition, the section will seek to understand the relationship that has been in place between Syria and Lebanon over a couple of years. This is important in determining the dynamics of the relationship of the two countries from pre-war and during the warring time. This paper will establish the importance the information obtained from the study on the international point of view about the war. At the same time the paper will highlight the importance of the information on both the Syrian and Lebanon authorities. Perhaps this will make them make better decisions that might help in mitigating the effects of the war. Lastly, it

Smoking Cessation Research Paper Example | Topics and Well Written Essays - 500 words - 2

Smoking Cessation - Research Paper Example Some other things that the author did was making observations in the field, which included paying close attention to the conversation between the patients and the nurses, making observation of the signs that were placed within the walls of the wards that were in relation with the tobacco restrictions as well as taking of notes of resources that addressed cessation. Some of the documents that were collected during this study included; patient care forms, admission forms, referral forms, and patient’s referral materials. Areas like designated smoking zones were also observed and further photographed. At some point, unstructured questionnaires were presented to the nurses, which lasted for between 10 to 30 minutes. The ethnographic analysis used a process known as non-linear inductive. This included sorting, coding, theorizing as well as reflection upon analytic process. The data set in this study included documents, hand recorded conversation, field notes as well as the photographs that were captured designated smoking zones. At first, several data sets were reviewed. After that, the data was coded with the help of key concepts that facilitated retrieval as well s comparison between two sites. Other more reviews were conducted, which was then used to conceptualize the whole concept. The use of conversation in observation presents some bias. This is because the individuals involved in the process may assume different roles when they realize that they are being studied. This is one of the challenges that the ethnographer faced while collecting data. Taking of photos presented a good opportunity for the ethnographer to find the information they needed in their natural setting. Use of unstructured questionnaire was a good attribute to ensure that the qualitative analysis was conclusively done. The ethnographer noted that while the nurses were talking about tobacco in hospital environment, struggle was made to make

Ecosystem Components Essay Example | Topics and Well Written Essays - 750 words

Ecosystem Components - Essay Example The sustenance of this park depends on the cooperation of people living in the area, and the activities of the government to protect it (Boarman & Coe, 2002). This paper will examine the characteristics of this ecosystem, and the plans that are in place to ensure that it continues to sustain life in that area. The major structural and functional dynamics The massive dry land that is the Mojave Desert makes the Joshua Tree National Park a beautiful sight. This area is the special habitat for the Joshua Tree, which is also known as Yucca brevifolia. Geological displays, such as hills of unadorned rock, are also part of this environment. The functional dynamics of the ecosystem border on the competitiveness of the living things in the habitat. Living things, for example plants, have to be competitive in their quest to retrieve sunlight. Over some time, the plants in this area have to adapt to the environment to reduce their exposure to sunlight. It is through this adaptation that they a re becoming a part of the ecosystem’s food chain. Ravens stand out with an increase in population in the ecosystem. An imbalance in such may lead to an alteration in the ecosystem’s food chain as there might start being a decrease in the tortoise population (Fontaine et al., 2011). How humans may have affected biogeochemical cycles Over the years, humans have been affecting the biogeochemical cycle that exists in this natural habitat. For instance, the driving of vehicles in this habitat at high speeds has led to the death of a number of animals, for example tortoises. The decomposition of these animals leads to the disruption of the carbon cycle that is present in the area. The carbon, phosphorus, and nitrogen cycles are affected as the decomposition of these animals tie to biological matter, causing a release of carbon dioxide gas into the ecosystem. Fires are another way in which individuals affect the ecosystem’s gas cycles. The burning of dry plants makes i t difficult for the ecosystem to sustain itself as the primary producers are being eliminated. Also, the acidic nature of the fumes released into the atmosphere in such an ecosystem may prove challenging to the phosphorus cycle that exists (Fontaine et al., 2011). How knowledge about JT National Park can help or has helped to develop plans for its management and restoration In the 21st century, it is particularly crucial for individuals to help in the restoration and management of national parks. The educational programs in institutions are being re-examined to allow different areas to bring focus to the preservation of national parks, and other natural habitats. Since parks are a place where basic biology can be observed, learners are engaged through visits on a regular basis. By understanding the dynamics surrounding the JT National Park, individuals might be keen on trying to be more cautious as they drive through the desert or its environs. The terrain may be difficult to compre hend and this makes it even more tedious in trying to educate people. However, by having the locals in that area take the initiative to act as guides, it may be possible to avoid some of the human acts that may work against nature (Boarman & Coe, 2002). Forest fires, a thing that is common, should be a thing of the past. People should become more self-aware of the threats they pose. The implication of species interactions in ecosystem management and re

Personality Inventories Reliability, Validity, Correlation Essay

Personality Inventories Reliability, Validity, Correlation - Essay Example There is much that can be postulated concerning these two groups. The GESS questionnaire is an adaptation of Hale, Fiedler and Cochran's 25 item inventory (Hale, Fiedler & Cochran, 1992). This inventory is a measure of the optimism that an individual possesses concerning the likelihood of achieving goals in life. A person with a high GESS score has a great degree of optimism in their own ability to complete a task. While a person with a low GESS score is considered to be pessimistic about their own ability to reach a desired goal. Participants were selected randomly from the classroom. Of the 17 subjects participating in this study, 6 were male and 11 were female. Ages ranged from 19 to 30 years old. Two personality inventories were used in this study, the Internal Control Index and the Generalized Expectancy for Success Scale. Each test subject was seated in a relatively quiet and secluded environment and asked to fill-in the answers on the two separate inventories. The results of the first administration of the test questions are shown in Figure 1. GESS numbers and ICI numbers were calculated by hand scoring each questionnaire. GESS scores ranged from 86 to 149, out of a possible range of 30 to 150.

Human Cloning Essay Example | Topics and Well Written Essays - 1750 words

Human Cloning - Essay Example Besides therapeutic and reproductive cloning another category of cloning called the replacement cloning is also gaining prevalence. Replacement cloning is an amalgamation of therapeutic as well as reproductive cloning. The term gained prominence as it involves comprehensively injured, abortive, or weakening body, and replacement of the whole or partial organ or part of the body. The present article discusses the pros and cons of human cloning while extracting attention to understand the significance of human cloning in the advancement of human civilization. Human cloning is the process of generating a genetically indistinguishable replica of human being. It is a technique of imitating genetic information (Roxanne, 2010). The process is thought to be of therapeutic or reproductive importance. Therapeutic cloning encompasses cloning cells for their exploitation in treating various ailments. On the other hand reproductive cloning generates human clones, this is prohibited in many nation s because of ethical concerns. The moral predicament of human cloning lies on the argument either to promote or to impede cloning (Robert, 2001). Numerous molecular techniques are involved in the process of cloning encompassing molecular cloning, reproductive cloning and therapeutic cloning (Manninen, 2010). There are numerous controversies associated with the cloning procedures some may favor cloning while others oppose the same. The present thesis discusses various aspects of the cloning as 1. The Cons/ Problems/Dangers and Controversies of Cloning a. Cloning is discouraged by various nations as cloning is against the rule of nature, which is generating humans, nurturing them and paving the way for uncertainties related with the repercussions of science. At present human population has crossed the figure of 7 billion, a huge burden on the planet. Is cloning going to resolve the issue of exponentially increasing human population is a big question imposed by the detractors of human cloning (Gary, 2012). b. Detractors of human cloning have their say about the loss of genetic diversity leading to higher probability and pervasiveness of genetic diseases. Poor adaptability of clones may become detrimental for situations of jeopardy. Inbreeding leads to self-annihilation. c. Cloning is inhumane as it abolish the bond of love and care and is said to be transgressing the nature. The process of cloning highlight that the human or scientists can play the role of Creator or God as cloning is a kind of asexual reproduction, therefore reduces the sense of distinctiveness of a character, lacking uniqueness and freedom. It is also noteworthy to have an insight regarding the amplification in human population and ecological burden on resources and on other surviving species. Growing population is putting pressure on the demands of basic amenities, infrastructures and social set ups; with human cloning, further contribution to disaster cannot be eluded. According to Savulescu (1999), human cloning is accountable to abuse, a person's right to individualism and self-sufficiency and being self is violated, moreover genetic individuality is also lost and human beings are used as a model organism. Cloning also enhances the risk of self safety due to genetic irregularity, cancer and diminished lifespan. 2. Pros/ Advantages of Cloning a. According to

Personality Inventories Reliability, Validity, Correlation Essay

Personality Inventories Reliability, Validity, Correlation - Essay Example There is much that can be postulated concerning these two groups. The GESS questionnaire is an adaptation of Hale, Fiedler and Cochran's 25 item inventory (Hale, Fiedler & Cochran, 1992). This inventory is a measure of the optimism that an individual possesses concerning the likelihood of achieving goals in life. A person with a high GESS score has a great degree of optimism in their own ability to complete a task. While a person with a low GESS score is considered to be pessimistic about their own ability to reach a desired goal. Participants were selected randomly from the classroom. Of the 17 subjects participating in this study, 6 were male and 11 were female. Ages ranged from 19 to 30 years old. Two personality inventories were used in this study, the Internal Control Index and the Generalized Expectancy for Success Scale. Each test subject was seated in a relatively quiet and secluded environment and asked to fill-in the answers on the two separate inventories. The results of the first administration of the test questions are shown in Figure 1. GESS numbers and ICI numbers were calculated by hand scoring each questionnaire. GESS scores ranged from 86 to 149, out of a possible range of 30 to 150.

Week 6 Response papers Essay Example | Topics and Well Written Essays - 500 words

Week 6 Response papers - Essay Example Business organizations should engage in environmental conservation at any time, not just after major environmental concerns as witnessed at BP. Companies should get involved in environmental conservation as a way of being socially responsible. Companies should be exemplary and constantly embrace the principles of social responsibility. They should not just engage in environmental conservation so as to win more customers. Business organizations should engage in sustainability programs which are aimed at solving problems related to renewable energy, air quality management and water management. Other issues that they should be involved in include waste management and stakeholder dialogue to ensure that the general public is satisfied with the organizations efforts in conserving the environment (Woodward & Skancke, 2006). The only way business organizations can be said to be environmentally sustainable is to constantly get involve in waste elimination. Waste elimination should not only be carried out when business organizations are in crisis or after crisis. Some organizations such as BP only got involved in waste elimination after the oil spill crisis. There might be other minor oil spills that were not in large scale which went unchecked because the public were not aware of BP’s plans and willingness in waste reduction (Egendorf, 1999). On Leslie’s post, business organizations should actually integrate into their system, the power to make environmental decisions. In light of last year’s oil spill BP’s rebranding looks like it is just for gaining lost image after the oil spill. The values of branding only ensure that the company is able to win back its customers. Their most important aim is to make steady gains in revenues by winning customer tastes and preferences. Environmental conservation, even if used as a marketing strategy should look genuine. Even though the value of BP Beyond petroleum brand is proven in a chart published by

Food waste Essay Example for Free

Food waste Essay Fresh vegetables, ready-to-cook meals, and cheap meat is what a modern consumer’s supposed grocery list comprises of! Dump it all into your fridge full of deals, discount offers and feel happy. This is how the shop keeper gets a loyal customer. At the end o the story, it’s the food industry’s creed that the customer is always right†¦.. If food became it s own pungent country, it would be the world’s third biggest contributor to climatic changes. According to United Nations Food and Agriculture Organization, one-third of the world’s total food is wasted around the world, literally to fork direct from the farm. In West, most of the food waste occurs because usually the leftover ingredients are tossed out. The major reason for food wastage is that the harvest of a farmer does not meet the retailer’s specific demand. Considering tomatoes, if too small or even too big to be sold to retailer will be left to rot in fields. Whilst, in developing countries the scenario is a little different because the food rots between fields and markets due to shortage of storage capacity. Awareness campaigns regarding food waste have already begun in the Western part of the world. Organizations are educating people about the waste of food at household level and how can it be eliminated or reduced to an extent. This is just the bit of the whole chunk. Even supermarkets are playing their part by producing recipes to use leftover food and pamphlets to store your food in the best possible manner. Likewise, many grocery stores have initiated redistribution of unsold stocks and excess to charitable organizations. Looking at food waste in local context, Pakistan is also the culprit for this wastage in spite of the fact that underfeeding and food shortage are areas of serious concern. Although we produce adequate food for our nation but still the wastage level is at its peak. This is because of careless attitude of our state and our society’s love for excess food. When we talk about consumption of food, negligence by society also needs to be tackled. At social events as well as weddings, it is quite usual for people to pile up a mountain of food on their plates and eat just a portion of it as if this is the last time they are eating food. Much is needed to done to store perishable items such as fruits and vegetables. State needs to look into this matter with utmost care and also to preserve grains by creating extra facility for storage purpose. On collective basis, way of thinking needs to be changed. It is not only unethical but also an act of being socially irresponsible to waste food when millions around the world sleep empty stomach. According to Tim Lang, professor at City University London, food waste is a symptom, not a problem. So to eradicate these symptom governments, non-governmental organizations like UN can discourage wasteful exercises by producers of the food, farmers, consumers and grocery stores. Food spoiling and wasting is causing physical destruction to mother earth. So let’s join hands to exterminate wastage of food for those who starve and are under privileged.

A Mother Diagnosed With Cancer Psychology Essay

A Mother Diagnosed With Cancer Psychology Essay At that time, cancer for me and probably for anyone else was an unknown monster who spared no life when it hits you. There were endless nights full of hope for her recovery. At night before I would doze off to sleep I would look at her closely. She still had that same pretty face, beautiful eyes, lovely shaped lips and brilliant mind. But deep inside, it was too painful to see my ever energetic mother lying in bed with all the tubes in her body. Too hurtful to think that all we had shared, our plans might come to an endà ¢Ã¢â€š ¬Ã‚ ¦ This is an adolescent daughters account of her journey with having a mother diagnosed with cancer. Dealing with maternal cancer can cause distress and anxiety because this illness is usually associated with poor prognosis, agonizing pain, negative effects of the treatment, and low survival rates. Cancer is considered by many as a silent killer, which unsuspectingly ravages the body from within. It can be a stressful experience, not only for the patients themselves, but also for the entire family. Every member of the family, especially the children, has to adjust to the emotional burden, physical demands, and lifestyle changes which cancer brings about. The occurrence of cancer has alarmingly increased throughout the years, affecting and claiming many lives around the world. It has been estimated that around 12.2 million people are diagnosed with cancer worldwide (American Cancer Society, 2007). It is also projected that the number of cancer cases and deaths will continue to escalate in the future. New cancer cases are estimated to increase from 11.3 million in 2007 to 15.5 million in 2030 (WHO, 2008). Based on the worldwide proliferation of cancer cases, this disease is now considered to be a major health problem. In the local scene, it is estimated that one in every 1,800 Filipinos will suffer from cancer every year (Philippines Breast Cancer, 2008). Based on the 2005 Cancer Facts and Estimates (cited in A Look at Cancer, 2007), approximately 39,929 men and 32,917 women were diagnosed with cancer that year. Consistent with the worldwide trend, the number of cancer patients in the Philippines is also expected to increase in the coming years. The most common cancer sites for both men and women are as follows: lung, breast, liver, cervix, and colon (A Look at Cancer, 2007). Young and middle-aged women are at great risk of developing cancer. According to Hamouy (2007), statistics show that females have one in three chances of getting cancer in their lifetime. This risk is also due to the drastic increase in the number of breast and cervical cancer cases, which are commonly and specifically associated with women. The breast is the most common cancer site among Filipinas. As of 2008, the Philippines had the highest reported cases of breast cancer in Asia, even surpassing other European countries (Philippines Breast Cancer, 2008). Cervical cancer ranks as the second most frequent type of cancer among Filipino women (World Health Organization, 2007). According to the Department of Health (cited in DOH Launches, 2008), approximately 10 Filipinas die from cervical cancer each day. Women diagnosed with cancer belong to various age groups. However, findings consistently show that cancer risk is positively correlated with age (Baum Andersen, 2001; A Look at Cancer, 2007). This puts older women at greater risk for developing this dreaded disease. In the past years, majority of cancer cases were diagnosed at 50 years old or at a postmenopausal age (Bobadilla, 2006). Unfortunately, there has been an increase in the occurrence of cancer among women in their midlife (Bobadilla, 2006) as well. Recently, the battle against cancer has started to affect younger women. A significant number of women who belong to this population are mothers. It is estimated that 30% of women diagnosed with breast cancer has one or more dependent offspring still under her care (Faulkner Davey, 2002). The growing incidence of cancer among younger mothers means that more families are being challenged to cope with this disease. Mothers diagnosed with cancer are faced with various issues in the different facets of their lives. On a personal level, their concerns include experiencing the physical rigors of the disease and treatment, emotional issues, and preoccupation with existential matters. Aside from these, they also have additional sources of stress such as meeting the demands of being wives, mothers, and professionals in their respective fields. Being diagnosed with cancer at this stage in ones life can be stressful and in some cases, traumatic. This can be attributed to the pressure of having to fulfill different roles despite the physical and emotional demands of the disease. Mothers with cancer are forced to shift their role from taking care of their family to the one being cared for. In effect, although a maternal cancer diagnosis is experienced as a personal crisis, it also makes a great impact on the whole family system. These families are put in a predicament wherein they have to adapt with the changes and stresses brought about by maternal cancer. As the patients roles as a mother and spouse are disrupted, dealing with the illness becomes a shared crisis within the family. The husband and children are forced to adapt with the situation by handling the responsibilities which the mother could not perform, while dealing with their own emotional distress. The stressful nature of the situation puts other family members at risk for psychological distress, especially the children. In families dealing with maternal cancer, the adolescent daughters are expected to assume the responsibilities of the mother. In the Filipino culture, daughters are reared to help out in domestic chores and assist the mother with her duties (Liwag, Dela Cruz, Macapagal, 1998). Thus, when the mother is not well enough to carry out her responsibilities, adolescent daughters take over in caring for the family. This additional burden makes adolescent daughters the most vulnerable to experience psychological distress. Such circumstances subject the daughters to witness drastic physical and emotional changes in their mothers, disruption in their daily routines and changes in family roles. Aside from sharing the burden with their family, the daughters are also faced with the challenge of dealing with the developmental demands of being an adolescent. They may experience a variety of emotional responses, the most common of which are depression and anxiety, as a way to cope with their stress. Parents may fail to recognize the distress their daughters are experiencing due to preoccupation with the treatment and their own distress. In effect, the emotional issues harbored by the daughters may not be addressed appropriately. In the field of psychological research, a large body of studies had already been devoted to investigating the effects of cancer on the different aspects of a patients life. It has only been recently that researchers also recognized the need to shift their attention to the children of cancer patients. It is in this vein that the focus of this research will be centered on adolescent daughters whose mothers have cancer. This research will look into the psychological impact of maternal cancer on adolescent daughters, specifically in terms of emotional, behavioral, and social functioning. The mothers perceptions regarding how their daughters are dealing with situation will also be explored. It is also of interest to know how maternal cancer affects the relationship between the mother and adolescent daughter. Review of Literature Impact of Parental Cancer on the Family Cancer was found to be associated with psychological distress. Much of past research on cancer has focused mainly on the psychological impact of cancer on the patients themselves (Veach, 1998). Researchers have acknowledged that it is also necessary to look into the effect of cancer within the context of the family. Family Systems Theory The family is defined by Buckley (as cited in Papadopolous, 1995) as a system made up of sets of different parts which are interdependent and interconnected. A change in one part causes a change in the entire system. It is comprised of several subsystems which characterize the existing relationships within the family such as parental, marital, and sibling relationships (Faulkner Davey, 2002). According to the family systems theory, the condition of one family member influences the condition of other family members. It proposes that all the subsystems within the family interact and affect each other (Faulkner Davey, 2002; Papadopolous, 1995). The members of the family operate in a way that it maintains a balanced level of functioning, also known as equilibrium. The well-being of the family members and the familys functioning depend greatly on the interaction of the subsystems (Faulkner Davey, 2002). Due to the dynamic and interdependent nature of the family system, the roles and psychological functioning of individual members can affect the whole system. A role change initiated by one member will alter how the rest of the members play their roles. In this case, the whole system has to make corresponding changes in their behavior in order to compensate for the disruption in the roles among the members. This adjustment has to be made in order to regain the familys equilibrium (Jolley Mitchell, 1996). In the same way, a members psychological functioning is strongly influenced by ones interaction with the other members (Oster Caro, 1990). In families which are under a great deal of stress, the child is vulnerable to everything that is going on between the parents. The tension or conflict within a family can also induce distress within the child, whether the child is directly exposed to the stressor or not (Sokolova, n.d.). The Filipino Family The Philippine society is familial in nature (Jocano, 1995). Filipinos recognize that the family is the most basic institution in the society and is at the center of the affairs of the community. The high regard given to the family can be seen in the strong and pervasive influence this institution exerts towards individuals. According to Jocano (1995), the Filipino family is superordinate over the members. The life of each member is strongly influenced by the dynamics within the family. An individual must involve the family in decision-making and resolution of important issues. This is because the entire family is affected if something happens to its member, regardless of whether this occurrence is positive or negative. Thus, the Filipino family tends to be protective of its members, as a way to preserve not only the individual but the entire system as well. In order to uphold the traditional Filipino family system, cultural ideals which guide ones behavior are instilled in the individual. These ideals are learned through rearing practices and adherence to the societys norms. The following standards are honored and imbibed by traditional Filipino families: kapwa, damdamin, anddangal (Jocano, 1995, p.7). Kapwa refers to establishing interpersonal relationships which are based on equality and empathy. Damdamin on the other hand, deals with valuing others peoples emotions and striving in order not to hurts the feelings of others. Lastly, dangal, pertains to honoring and respecting others. Despite the changes in the society, in light of modernization, Jocano (1995) found that many Filipino parents continue to inculcate the following cultural ideals to their children: paggalang, which is giving respect to people and venerated customs; pagbabalikatan, which is empathizing and sharing the burden of others; pagbabayanihan, which is cooperating w ith one another; and pagmamalasakit, which is being considerate and concerned with other peoples welfare (Jocano, 1995, pp.7-8). The Filipino family is also described to be bilateral (Jocano, 1995). This refers to the establishment of close relationships with relatives from both the sides of the mother and father. An individuals level of affinity towards the maternal and paternal relatives are said to be equal. This bilateral characteristic of the family makes the relationships within the family system wider and more intertwined. In effect, the typical Filipinos concept of family is not only limited to the nuclear family structure, which is comprised of the parents and their children, but also includes the extended family which includes the relatives from both sides. By going beyond the immediate family, the individual can draw support and security from both the immediate and extended family. Jocano (1995) considers this close kinship among Filipinos as a significant source of strength. This provides an individual with an assurance that there will always be someone to count on when problems arise. The close ties among relatives and the ideals which families uphold influence the structure of Filipino households (Torres, 1995). It is typical for a nuclear family to share a roof with a few relatives and a nonrelative, which is usually the househelp. This is true, most especially for middle class urban families. In some cases, nuclear families who belong to the same clan reside in separate dwellings which are close in proximity. By maintaining geographical nearness, the extended family and its members are able to strengthen the support that they derive from each other. Carandang (1987) applied the family systems approach within the context of Filipino families. In line with Western theories on family systems, she suggested that any stress experienced by one member can be vicariously felt by the other members. Each of the family members responds to this stress by acting out in their own unique way. It has to be taken into consideration that the Filipino family is usually comprised of immediate family members, as well as extended relatives. There is also greater emphasis on maintaining close emotional bond among the family members. This nature of Filipino families makes it a more dynamic and complicated system. In effect, the children are challenged to gain recognition so as not to be lost within the larger system. This makes the children the most vulnerable members of the family because they can be easily affected by the stresses experienced by the family (Carandang, 1987). When the family is in the middle of a crisis, there is a tendency for the children not to directly articulate their feelings, especially if these are negative and are felt towards the adults in the family. In some cases, these stresses are manifested through the childrens behavior. Carandang (1987) found out that regardless of the socioeconomic status of the family, the children play the role of the familys protector. Being the protectors, the children absorb the familys stress and respond through their behaviors. In the Philippine setting, the familys tagasalo (Carandang, 1987, p. 47) or the one who takes care of the family is considered to be at risk for developing distress. Older siblings, most especially the daughters, are commonly expected to fulfill the role of being the familys tagasalo. Daughters are groomed at an early age to assist in tasks which are domestic and nurturant in nature, such as household chores and caretaking duties. By the time Filipino daughters reach adolescence, they are expected to become mother substitutes (Liwag, Dela Cruz, Macapagal, 1998, p.155). With this new role, adolescent daughters assume a considerable number of their mothers household responsibilities. The study of Go Tian (2003) supports Carandangs premise that daughters are more likely than sons to assume the role of the tagasalo. Based on her research among Filipino college students, females exhibited higher tagasalo traits than males. In contrast, Udarbes (2001) research proposed that the familys tagasalo is not necessarily related to the childs gender or birth order. Her findings suggest that the tagasalo generally possesses the following characteristics: strong sense of responsibility, good listener, nurturant, peacemaker and a strong need for control. Traditionally, women are considered to be central to the functioning of the family. This is due to gender role socialization, which dictates that women are expected and trained to take care of household matters (Liwag, Dela Cruz, Macapagal, 1998). As the major female figure in the family, the mothers main role is to handle domestic responsibilities at home. Thus, when a mother is diagnosed with cancer, the family adapts to the situation by assuming the responsibilities which the mother could not handle. This burden is often passed on to the adolescent daughter, who had been trained since childhood to carry out domestic chores. The impact of cancer within the Filipino family was evident in a local study done by Gorospe (2002). A cancer diagnosis affects the different aspects of a patients life, as well as the rest of the family members. The debilitating effect of cancer on the patient can cause a disruption in routine, changes in lifestyle, and limitations in performing ones responsibilities. Thus, the patient and his family are confronted with overwhelming changes which they have to adjust to. As a reaction to these changes, the entire family undergoes a process of emotional distress characterized by disbelief, denial, and initial resistance to the diagnosis. The roles within the family also have to be re-assigned in order to compensate for the changes related to the patients inability to fulfill ones role. Family Changes Brought About by Parental Cancer A mothers diagnosis of cancer is not an individual struggle. The entire family is subjected to the repercussions of dealing with maternal cancer. According to Robinson, Caroll, and Watson (2005), cancer within the family can be considered as an emotional crucible. This is the shared experience in which the family goes through a series of emotional adjustments. Such experience has been described as both draining and empowering, not only for the cancer patient but for all the family members. The profound stress brought about by the illness affects the relationships and interactions within the family. As a response, the family members reactions are manifested through their behavior and emotions (Sargent, 2003). Parents diagnosed with cancer reported that due to the illness, they were unable to spend time with and address the needs of their children (Walsh, Manuel, Avis, 2005). This was supported by the study of Faulkner and Davey (2002) which revealed that parental cancer can lead to impaired parenting. The demands of the illness made both the healthy and ill parents less available to their children, emotionally and physically. There were also cases of less communication, decrease in supervision, and lack of consistency in discipline and nurturance. Such disruption in the family system undeniably exposes the children to many psychological stressors such as: threat of permanent loss of parent to death, temporary loss of parent due to the treatment demands, and changes in family roles and routines (Davey, Askew, Godette, 2003). This may result in adjustment difficulties and psychological consequences, thus, making the children vulnerable to the impact of having a parent with cancer. Cancer blurs the roles in the family. The study of Walsh, Manuel, and Avis (2005), which investigated the impact of maternal breast cancer on the family, revealed that because the mothers were not well enough to perform their usual responsibilities at home, they had to transfer some of their family duties to their spouses and children. Generally, adolescents in the family had to take on more responsibilities at home, such as household chores and caregiving tasks for their younger siblings and the ill parent (Davey, Askew, Godette, 2003; Davey, Gulish, Askew, Godette, Childs, 2005; Grabiak, Bender, Puskar, 2007; Visser, Huizinga, Van der Graaf, Hoekstra, Hoekstra-Weebers, 2003). Aside from dealing with worry over the ill parents condition, the adolescent children in the family felt that their lives were complicated due to the additional responsibilities they had to carry out in order to augment the deficiencies caused by maternal cancer (Davey, Gulish, Askew, Godette, Childs, 2005). Psychological Adjustment Among Adolescents of Cancer Patients The psychological effects of maternal cancer on children are widely investigated. The qualitative study of Forrest, Plumb, Ziebland, and Stein (2006) reported that children already suspected that something was wrong even before they were told about their mothers diagnosis. They based this suspicion on the mood and behavior changes in their mother. Upon knowing about the maternal cancer diagnosis, the adolescents experienced emotional distress. The initial emotional responses were shock and disbelief, followed by devastation and intense feelings of sadness (Davey, Askew, Godette, 2003; Davey, Gulish, Askew, Godette, Childs, 2005). Compas, Worsham, Ey, and Howell (1996) assessed the emotional distress experienced by children of cancer patients by looking into their depression and anxiety. Their distress arose from their considerable worry about their mothers health and fear of losing their mother from cancer (Davey, Askew, et al., 2003; Davey, Gulish, et al., 2005; Grabiak, Bender, Puskar, 2007; Kristjanson, Chalmers, Woodgate, 2004; Walsh et al., 2005). In some studies, adolescents were also concerned with the possibility of potentially inheriting the cancer (Davey, Askew, et al., 2003; Walsh et al., 2005). The adolescents emotional difficulties partly stemmed from feeling powerless over their parents illness. The adolescents felt that they did not have control over the outcome of the diagnosis and treatment, which in turn also affected the moods and accessibility of both parents (Davey, Askew, et al., 2003). Another cause of the adolescents distress was witnessing their parents pain. Some of the adolescents reported that they were bothered by the side effects of chemotherapy (Forrest et al., 2006). They had to adapt to seeing their usually healthy parent slowly become weak and ill (Davey, Askew, et al., 2003). The positive effect this had on the children was that they became more empathic towards their ill parent. They were also more tolerant and understanding of both their parents, who exhibited increased irritability and moodiness (Davey, Askew, et al., 2003). This was consistent with the findings of Kristjanson et al. (2004) which revealed that the adolescents were sensitive to the suffering of their ill mother. The teenagers expressed that they felt guilty because their own lives were normal, whereas their mother was enduring the painful physical and psychological consequences of cancer. They were able to empathize with their mothers suffering but they expressed guilt about their own situation. A local research done by Tantoco (1992) examined the issues confronted by terminally ill mothers and their eldest offspring. Results revealed that the eldest children exhibited considerable anxiety during the process of dealing with their mothers illness. Many of the participants described their journey as an emotional roller coaster ride (Tantoco, 1992, p.73). This experience compelled them to prioritize their mothers condition. This forced them to put other aspects of their lives, such as studies, work, and heterosexual relationships aside. Given that the eldest children focused much of their attention on their ill mother, they became sensitive to their mothers physical, emotional, and mental anguish. The children shared that they had difficulties in dealing with their ill mothers emotional outbursts. Despite this, the eldest in the family also felt the need to give emotional support, security, and assurance to their ill mother. Another source of the eldest childrens stress was the ir informal role of being next to their parents in terms of responsibility and authority. Being the eldest, they had to take on additional household responsibilities, including caring of their ill mother and younger siblings. These extra tasks required them to make personal sacrifices such as not being able to engage in their usual adolescent activities. Aside from emotional problems, behavioral changes were also observed among children of cancer patients. Increased crying, clinging, difficulty in sleeping, and changes in the intensity of talking were some of the behaviors which children engaged in after their parent was diagnosed with cancer (Visser et al., 2003). There are inconsistent findings in terms of the childrens school performance. Some adolescents showed a decline in their academics and attendance (Visser et al., 2003; Grabiak, Bender, Puskar, 2007. This was due to their inability to concentrate during school hours because of their preoccupation with their parents illness and the disruptions in their routine (Visser et al., 2003; Forrest et al., 2006). However, some adolescents actually performed better in school even though they were dealing with parental cancer (Visser et al., 2003). Positive behavioral changes also surfaced as the adolescents were dealing with their mothers cancer. The adolescents expressed that they appreciated their mother more even when the diagnosis and treatment were over. They showed this newfound appreciation by constantly checking on how the ill mother is doing, wanting to be physically close, paying more than usual attention to mothers needs, and wanting to offer support (Visser et al., 2003; Davey, Gulish et al., 2005). Some adolescents also reported that they took over their mothers role even if it meant an increase in their responsibilities. This contributed to their perception that they were older than their years, after having gone through that experience (Davey, Gulish et al., 2005). Daughters whose mothers have cancer also became more involved with the medical aspects of the treatment. Even though they were less convinced that things will work out, they took more initiative in handling the medical concerns of their mother (Gilbar Borovik, 1998). According to Grabiak, Bender, and Puskar (2007), the behavioral adjustment of adolescents rely heavily on the emotional condition of both parents and on the family functioning. When both parents display symptoms of depression, adolescents tended to show increased behavioral problems. Between the two parents, maternal depression exerts a stronger influence on the childs behavioral functioning. It was also found that adolescents who experienced difficulty with behavioral adjustment perceived their families as having poor quality of communication, responsiveness, and involvement. In the aspect of social functioning, the study of Osborn (2007) found no evidence to suggest that social competence is negatively affected among children of cancer patients. In a few studies, adolescents of cancer patients even reported handling their social lives more effectively than those from the norm groups (Osborn, 2007). This favorable social functioning may be attributed to the strong social support which the adolescents actively seek and maintain. Common sources of social support were family, friends, school counselors, teachers, and support groups (Davey, Askew, Godette, 2003; Grabiak, Bender, Puskar, 2007; Huizinga, Van der Graaf et al., 2005). Adolescents felt that their peers were positive sources of support with whom they could talk openly about their feelings and fears. However, some teenagers expressed that their friends had difficulty empathizing with their situation. They felt that their friends could not really understand what it is like to have a mother diagnosed with cancer. This feeling further highlights the sense of isolation which the adolescents sometimes feel. They felt more consoled when they talked to peers who were also experiencing the same adversity (Huizinga, Van der Graaf et al., 2005). Similarly, Filipina adolescents place importance on having strong social ties. Being more emotionally involved in relationships and having higher levels of interpersonal needs, warmth, and sensitivity are important factors which contribute to the finding that female adolescents are less lonely than their male counterparts. Their need for interaction actually reduces the feelings of loneliness because Filipina adolescents have a richer source of social and emotional support (Jimenez, 2009). Adolescents of Cancer Patients in Comparison With Control Groups Several studies compared the psychological functioning of adolescents whose parents have cancer vis-a-vis a control group. Inconsistent findings were found. A number of studies reveal that adolescents of cancer patients and the control group did not significantly differ in terms of emotional, behavioral, and social functioning (Brown et al., 2006; Harris Zakowski, 2003; Hoke, 2001; Huzinga, Van der Graaf, Visser, Djikstra, Hoekstra-Weebers, 2005; Osborn, 2007; Visser, et al., 2007). The similarity in the levels of psychological distress between adolescents of cancer patients and the control group can be attributed to the childrens efforts to mask their true feelings. They were aware that their parents were already under a great deal of stress. The adolescents showed that they were not affected by the situation so that their parents would not worry about them. This was their way of protecting their parents from additional stress (Visser et al., 2007). Although no significant differences were found in terms of psychological distress, a percentage of the adolescents of cancer patients exhibited scores within the clinical range. In the study of Houck, Rodrigue, and Lobato (2006), one-third of the adolescents whose parents have cancer reported clinical levels of posttraumatic stress in response to their parents illness. In addition, approximately 25% to 30% of the adolescents in both the studies of Visser et al. (2007) and Huizinga, Van der Graaf et al. (2005) reported clinically elevated scores in internalizing and externalizing problems. Internalizing problems refer to turning ones emotions inward. This is manifested through withdrawal, somatic symptoms, anxiety, and depression. On the other hand, externalizing problems are more noticeable ways of dealing with stress because they are reflected through ones behavior. This can be in the form of socially unacceptable, delinquent, and aggressive behavior (Visser et al., 2005). Consisten t with the abovementioned, Osborn (2007) proposed that adolescents of cancer patients generally did not experience higher levels of psychological distress compared to reference groups. However, they were slightly at increased risk for internalizing problems. Some studies found that adolescents of cancer patients are more emotionally distressed than those from the control sample. The research of Grabiak et al. (2007) revealed that adolescents whose parents have cancer displayed a significantly higher level of anxiety compared to the age-normed sample. Visser et al. (2003) supported this claim as their study found that when compared to a control group, adolescents dealing with parental cancer exhibited significantly higher stress-response symptoms, which included avoidance and intrusive thoughts. In another study, adolescents of cancer patients also displayed significantly higher levels of perceived risk for developing cancer than adolescents who have healthy parents (Harris Zakowski, 2003). Despite this, it is interesting to note that these two groups did not differ in depression and anxiety. Hoke (2001) found that adolescents coping with maternal cancer did better in their social and academic endeavors when their mother was more distres sed. This is in comparison with adolescents in the control group who did less well when their mother was more distressed. The results also varied depending on the t

Rates of Reaction :: GCSE Chemistry Coursework Investigation

The rate of reaction is a measure of how fast something happens. We can find the rate of reaction by measuring the change that happens in a set period of time. Introduction ------------ The rate of reaction is a measure of how fast something happens. We can find the rate of reaction by measuring the change that happens in a set period of time. Many factors can affect the rate of reaction; the concentration of the reactants is one of them. In the following experiments we will investigate how the concentration of the reactants affect the rate of reaction. To do this we will use the reaction between magnesium and hydrochloric acid. GRAPH I will measure the rate of reaction by timing how long the reaction takes. Aim- I am trying to find out how an increase/decrease in concentration of the acid affects the rate of reaction in magnesium strips. Prediction: I predict that as the concentration of hydrochloric acid increases the time taken for the magnesium to dissolve will decrease. I also think that when the concentration of the acid doubles the rate of reaction will also double. Collision Theory: The collision theory is how the rate of reaction increases when the concentration of hydrochloric acid increases. In the reaction firstly all of the particles in the reacting substances must collide. They must collide with a certain amount of energy called activation energy, this must be reached for the reaction to take place. If the particles do not reach this required amount of energy there will not be any successful collisions and therefore the reaction will not take place. If the particles do reach the required amount of energy a reaction will rake place and as the number of collisions increase the reaction speeds up. The more concentrated the reactants the larger the number of successful collisions between the particles. This explains why the largest rate of reaction is usually as soon as the reactants have been mixed together, this means they are both at their highest concentrations. High concentration Low concentration (18cm ³ HCL + 2cm ³ H ²O) (6cm ³ HCL + 14cm ³ H ²O) The temperature in this investigation will not affect the rate of reaction because throughout the investigation it will stay at room temperature. If the temperature was to change during the experiment it would effect the rate of reaction by speeding it up if the temperature increased because the particles move a lot faster and travel a larger

A Mongoliod Child Handling Shells On The Beach by Robert Snyder :: essays research papers

Diction, Theme and Imagery in Richard Snyders Intro To Poetry "A Mongoloid Child Handling Shells on the Beach" When you first read Richard Snyders narrative poem, "A Mongoloid Child Handling Shells on the Beach", it may be perceived that the poem is indeed about a child, happily gathering shells upon the shore. However, if we closely consider the diction and connotations that Synder uses, we can speculate that the meaning of the poem depicts a deeper and darker theme. The title itself gives us an idea from the beginning. The word Mongoloid, as identified in Websters New World Dictionary (675), is an early term for Down's Syndrome, a state of mental retardation. Therefore I believe that the poem represents the child as an outcast from the norm of society. There are several words in the text that refer to the child that we usually wouldn't associate with youth. An early clue would again be found in the title, "A Mongoloid Child Handling Shells on the Beach". Notice that Snyder used the word "handling" instead of playing or collecting, words wich we might think of while envisioning a young girl investigating sea shells. Snyder also uses the word 'slow' to describe the child on more than one occasion, as we see in line one and line eight : "She turns them over in her slow hands/ ...hums back to it its slow vowels." Yet another example could be in line four, which reads: " they are the calmest things on this sand." Calm is yet another word that we would not most likely use to portray a young child. It very well could be that the author is trying to paint a picture of her impairment and symbolize her condition through her actions. Considering Snyder depicted the ocean as "..the mazarine maze,"(3) instead of simply stating that it is the "deep blue sea", it is easy to speculate that the ocean represents life itself. Her being outside of the water while all the other children are swimming is a key example of her being isolated. The way that she is presented, which is slow and rather solemn, contrasts with the other children who are "rough as surf, gay as their nesting towels."(6). I feel that this kind of symbolism is repeated throughout the remainder of the poem. The sea shells, for instance, are another important representation of her isolation. It reads in line three: " broken bits from a mazarine maze,". If we look at the mazarine maze as being life, and the shells are broken bits of it washed ashore, it becomes clear that

Well Hello There!

Dialogue (Feelings through words) Dialogue is one of the most powerful attributes an author can use while writing a story. It is a conversation between characters in a drama or narrative. Also, it’s the lines or passages in a script that are intended to be spoken. The use of this gives the reader the belief that they are part of the story. It is used throughout stories to convey the feeling of emotions.Writers use expressions in their writing to suggest that the character(s) are having some sort of inner feeling happening Whether it be from the author inserting some of his/her own words or the character talking, this technique gives the story more of a fluent feeling. With the story â€Å"A Conversation with My Father,† dialogue is used sufficiently throughout the reading. This is a literary work written in the form of a conversation. This conveys that this conversation between daughter and father is continuously arguing about a topic.In the story â€Å"A Good Man is H ard to Find,† dialogue is used in the way so the reader visualizes what the characters are talking about. Dialogue contributes to the overall story to keep the reader in and aware of the moods the characters are experiencing; it shows the true meaning behind the belief of the imagination. An exchange of ideas or opinions. Dialogue is a big contribution to the overall reading. It shows the inner linings of a story. In the story â€Å"A Conversation with My Father,† the dialogue is shown in the text through the talks between father and daughter.When the daughter says â€Å"I say, yes, why not? That’s possible. I want to please him, though I don’t remember her writing that way. I would like to try to tell such a story, if he means the kind that points which I’ve always despised (Poley 1096). † What the author does for this sequence of writing is the use of expression in the text. Even though this is writing on paper, the belief of emotion is see n. The daughter says â€Å"I say, Yes, Why not? That’s possible; the author wanted to convey the use of excitement and persuasion of the character and transfer that to the reader.Dialogue is shown in many ways. In â€Å"A Good Man is Hard to Find,† the author wants the reader to experience the story through the life and views of the Grandmother. She tried to convince her family to take a vacation to east Tennessee instead of Florida. Shown in the text, â€Å"The Grandmother didn’t want to go to Florida; she wanted to go to visit some of her connections in east Tennessee and she was seizing at every chance to change Bailey’s mind (O’Connor 1042). † The author shows you the want and the need of the grandmother to get to east Tennessee.In the eyes of the reader, the use of the text to show the emotion of the grandmother is nothing short of excitement. The Grandmother is excited to start the trip. For example, â€Å"The next morning the grandm other was the first one in the car, ready to go. She had her big black valise that looked like the head of a hippopotamus in one corner, and underneath it she was hiding a basket with Pitty Sing, the cat, in it (O’Connor 1042). † When it comes to the two stories relevance to each other; Dialogue is the link between them.Dialogue is used through-out both stories to make sure the reader understands what is going on in the story. The characters in the stories show their personalities, self-beings, and their love for one another (family wise). In â€Å"A Good Man is Hard to Find,† the family shows their love for each other and their personalities through the dialogue used by the author. The Grandmother starts to tell a story while the family is on the road trip. In â€Å"A Conversation with My Father,† the daughter and father have a relationship that is rocky.The use of subtext by the author shows a conversation between daughter and father. â€Å"Once in my t ime there was a woman and she had a son. They lived nicely, in a small apartment in Manhattan. This boy at about fifteen became a junkie, which is not unusual in our neighborhood. In order to maintain her close friendship with him, she became a junkie too. She said it was part of the youth culture, with which she felt very much at home. After a while, for a number of reasons, the boy gave it all up and left the city and his mother in disgust.Hopeless and alone, she grieved. We all visit her (Paley 1096). † This quote from the story represents the dialogue used by the author to convey a conversation being had between the father and the daughter. With this quote being in the story, the reader feels as if they are in the conversation too. The daughter and the father show their belief and love for one another even if their relationship is not the best. The father will always be her father and the daughter will always be his daughter.In Conclusion, Dialogue is one of the most power ful attributes an author can use while writing a story. It is a conversation between characters in a drama or narrative. Also, it’s the lines or passages in a script that are intended to be spoken. It is a powerful tool that the author uses to show the personalities and the beliefs of the characters in the writing through words. The use of this gives the reader the belief that they are part of the story. It is used throughout stories to convey the feeling of emotions.Writers use expressions in their writing to suggest that the character(s) are having some sort of inner feeling happening Whether it be from the author inserting some of his/her own words or the character talking, this technique gives the story more of a fluent feeling. With the story â€Å"A Conversation with My Father,† dialogue is used sufficiently throughout the reading. This is a literary work written in the form of a conversation. This conveys that this conversation between daughter and father is con tinuously arguing about a topic.In the story â€Å"A Good Man is Hard to Find,† dialogue is used in the way so the reader visualizes what the characters are talking about. Dialogue contributes to the overall story to keep the reader in and aware of the moods the characters are experiencing; it shows the true meaning behind the belief of the imagination. An exchange of ideas or opinions. Works Cited O'Connor, Flannery. A Good Man is Hard to Find. 8th ed. Boston, New York: Bedford/St. Martin's, 1999. 1042-53. Print. Paley, Grace. A Conversation with My Father. 8th ed. Boston, New York: Bedford/St. Martin's, 1999. 1096-1099. Print.

Transfer Functions

ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ TRANSFER FUNCTIONS AND BLOCK DIAGRAMS 1. Introduction 2. Transfer Function of Linear Time-Invariant (LTI) Systems 3. Block Diagrams 4. Multiple Inputs 5. Transfer Functions with MATLAB 6. Time Response Analysis with MATLAB 1. Introduction An important step in the analysis and design of control systems is the mathematical modelling of the controlled process. There are a number of mathematical representations to describe a controlled process:Differential equations: You have learned this before. Transfer function: It is defined as the ratio of the Laplace transform of the output variable to the Laplace transform of the input variable, with all zero initial conditions. Block diagram: It is used to represent all types of systems. It can be used, together with transfer functions, to describe the cause and effect relationships throughout the system. State-space-representation: You will study this in an advanced Control Systems Design course. 1. 1. Linear Time-Variant and Linear Time-Invariant SystemsDefinition 1: A time-variable differential equation is a differential equation with one or more of its coefficients are functions of time, t. For example, the differential equation: d 2 y( t ) t2 + y( t ) = u ( t ) dt 2 (where u and y are dependent variables) is time-variable since the term t2d2y/dt2 depends explicitly on t through the coefficient t2. An example of a time-varying system is a spacecraft system which the mass of spacecraft changes during flight due to fuel consumption. Definition 2: A time-invariant differential equation is a differential equation in which none of its coefficients depend on the independent time variable, t.For example, the differential equation: d 2 y( t ) dy( t ) m +b + y( t ) = u ( t ) 2 dt dt where the coefficients m and b are constants, is time-invariant since the equation depends only implicitly on t through the dependent variables y and u and their derivatives. 1 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Dynamic systems that are described by linear, constant-coefficient, differential equations are called linear time-invariant (LTI) systems. 2. Transfer Function of Linear Time-Invariant (LTI) SystemsThe transfer function of a linear, time-invariant system is defined as the ratio of the Laplace (driving function) U(s) = transform of the output (response function), Y(s) = {y(t)}, to the Laplace transform of the input {u(t)}, under the assumption that all initial conditions are zero. u(t) System differential equation y(t) Taking the Laplace transform with zero initial conditions, U(s) Transfer function: System transfer function G (s) = Y(s) Y(s) U(s) A dynamic system can be described by the following time-invariant differential equation: an d n y( t ) d n ? 1 y( t ) dy( t ) + a n ? 1 + L + a1 + a 0 y( t ) n ? 1 dt dt dt d m u(t) d m ? 1 u ( t ) du ( t ) = bm + b m ? 1 + L + b1 + b 0 u(t) m m ? 1 dt dt dt Taking the Laplace transform and considering zero initial conditions we have: (a n ) ( ) s n + a n ? 1s n ? 1 + L + a 1s + a 0 Y(s) = b m s m + b m ? 1s m ? 1 + L + b1s + b 0 U(s) The transfer function between u(t) and y(t) is given by: Y(s) b m s m + b m ? 1s m ? 1 + L + b1s + b 0 M (s) = = G (s) = U(s) N(s) a n s n + a n ? 1s n ? 1 + L + a 1s + a 0 where G(s) = M(s)/N(s) is the transfer function of the system; the roots of N(s) are called poles of the system and the roots of M(s) are called zeros of the system.By setting the denominator function to zero, we obtain what is referred to as the characteristic equation: ansn + an-1sn-1 + + a1s + a0 = 0 We shall see later that the stability of linear, SISO systems is completely governed by the roots of the characteristic equation. 2 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ______________ __________________________________________________________________ A transfer function has the following properties: †¢ The transfer function is defined only for a linear time-invariant system. It is not defined for nonlinear systems. The transfer function between a pair of input and output variables is the ratio of the Laplace transform of the output to the Laplace transform of the input. †¢ All initial conditions of the system are set to zero. †¢ The transfer function is independent of the input of the system. To derive the transfer function of a system, we use the following procedures: 1. Develop the differential equation for the system by using the physical laws, e. g. Newton’s laws and Kirchhoff’s laws. 2. Take the Laplace transform of the differential equation under the zero initial conditions. 3.Take the ratio of the output Y(s) to the input U(s). This ratio is the transfer function. Example: Consider the following RC circuit. 1) Find the transfer function of the network, Vo(s)/Vi(s). 2) Find the response vo(t) for a unit-step input, i. e. ?0 t < 0 v i (t) = ? ?1 t ? 0 Solution: 3 R vi(t) C vo(t) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Exercise: Consider the LCR electrical network shown in the figure below. Find the transfer function G(s) = Vo(s)/Vi(s). L R i(t) vi(t) vo(t) CExercise: Find the time response of vo(t) of the above system for R = 2. 5? , C = 0. 5F, L=0. 5H and ? 0 t < 0 . v i (t) = ? ?2 t ? 0 4 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Exercise: In the mechanical system shown in the figure, m is the mass, k is the spring constant, b is the friction constant, u(t) is an external applied force and y(t) is the resulting displacement. y(t) k m u(t) b 1) Find the differential equation of the system 2) Find the trans fer function between the input U(s) and the output Y(s). 5ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 3. Block Diagrams A block diagram of a system is a pictorial representation of the functions performed by each component and of the flow of signals. The block diagram gives an overview of the system. Block diagram items: Summing point Takeoff point Block Transfer function +_ The above figure shows the way the various items in block diagrams are represented. Arrows are used to represent the directions of signal flow. A summing point is where signals are algebraically added together.The takeoff point is similar to the electrical circuit takeoff point. The block is usually drawn with its transfer funciton written inside it. We will use the following terminology for block diagrams throughout this course: R(s) = reference input (command) Y(s) = output (controlled variable) U(s) = input (act uating signal) E(s) = error signal F(s) = feedback signal G(s) = forward path transfer function H(s) = feedback transfer fucntion R(s) Y(s) E(s) G(s) +_ F(s) H(s) Single block: U(s) Y(s) Y(s) = G(s)U(s) G(s) U(s) is the input to the block, Y(s) is the output of the block and G(s) is the transfer function of the block.Series connection: U(s) X(s) G1(s) Y(s) G2(s) 6 Y(s) = G1(s)G2(s)U(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Parallel connection (feed forward): G1(s) + U(s) Y(s) Y(s) = [G1(s) + G2(s)]U(s) + G2(s) Negative feedback system (closed-loop system): R(s) E(s) +_ The closed loop transfer function: Y(s) G(s) Y(s) G(s) = R(s) 1 + G(s) Exercise: Find the closed-loop transfer function for the following block diagram: R(s) Y(s) E(s) G(s) +_ F(s) H(s) 7 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) __________________________________________________________________ _____________ Exercise: A control system has a forward path of two elements with transfer functions K and 1/(s+1) as shown. If the feedback path has a transfer function s, what is the transfer function of the closed loop system. R(s) +_ Y(s) 1 s +1 K s Moving a summing point ahead of a block: R(s) Y(s) G(s) + R(s) Y(s) +  ± G(s)  ± F(s) 1/G(s) F(s) Y(s) = G(s)R(s)  ± F(s) Moving a summing point beyond a block: R(s) Y(s) + R(s) G(s) Y(s) G(s)  ± +  ± F(s) G(s) F(s) Y(s) = G(s)[R(s)  ± F(s)] Moving a takeoff point ahead of a block: R(s) Y(s) R(s) Y(s) G(s) G(s) Y(s)Y(s) G(s) Y(s) = G(s)R(s) 8 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Moving a takeoff point beyond a block: R(s) Y(s) R(s) Y(s) G(s) G(s) R(s) R(s) 1/G(s) Y(s) = G(s)R(s) Moving a takeoff point ahead of a summing point: R(s) Y(s) + Y(s)  ± F(s) R(s)  ± F(s) +  ± Y(s) + Y(s) Y(s) = R(s)  ± F(s) Moving a t akeoff point beyond a summing point: R(s) R(s) Y(s) + Y(s) +  ±  ± F(s)  ± R(s) F(s) R(s) + Y(s) = R(s)  ± F(s) Exercise: Reduce the following block diagram and determine the transfer function. R(s) + _ + G1(s) G2(s) G3(s) _ Y(s) + + H1(s)G4(s) H2(s) 9 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ Exercise: Reduce the following block diagram and determine the transfer function. H1 + R(s) +_ + G H2 10 Y(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 4. Multiple Inputs Control systems often have more than one input. For example, there can be the input signal indicating the required value of the controlled variable and also an input or inputs due to disturbances which affect the system.The procedure to obtain the relationship between the inputs and the output for such systems is: 1. 2. 3. 4. Set all inputs except one equal to zero Determine the output signal due to this one non-zero input Repeat the above steps for each of the remaining inputs in turn The total output of the system is the algebraic sum (superposition) of the outputs due to each of the inputs. Example: Find the output Y(s) of the block diagram in the figure below. D(s) R(s) +_ G1(s) + + H(s) Solution: 11 Y(s) G2(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) _______________________________________________________________________________ Exercise: Determine the output Y(s) of the following system. D1(s) R(s) +_ G1(s) + + Y(s) G2(s) H1(s) + + D2(s) 12 H2(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 5. Transfer Functions with MATLAB A transfer function of a linear time-invariant (LTI) system can be entered into MATLAB using the command tf(num,den) where num and den are row vectors co ntaining, respectively, the coefficients of the numerator and denominator polynomials of the transfer function.For example, the transfer function: G (s) = 3s + 1 s + 3s + 2 2 can be entered into MATLAB by typing the following on the command line: num = [3 1]; den = [1 3 2]; G = tf(num,den) The output on the MATLAB command window would be: Transfer function: 3s+1 ————s^2 + 3 s + 2 Once the various transfer functions have been entered, you can combine them together using arithmetic operations such as addition and multiplication to evaluate the transfer function of a cascaded system. The following table lists the most common systems connections and the corresponding MATLAB commands to implement them.In the following, SYS refers to the transfer function of a system, i. e. SYS = Y(s)/R(s). System MATLAB command Series connection: R(s) Y(s) G1 G2 SYS = G1*G2 or SYS = series(G1,G2) Parallel connection: G1 + R(s) SYS = G1  ± G2 or SYS = parallel(G1, ±G2) Y(s)  ± G2 Negative feedback connection: R(s) Y(s) +_ G(s) SYS = feedback(G,H) H(s) 13 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ R(s) Y(s) +_ G1 G2 H Example: Evaluate the transfer function of the feedback system shown in the figure above using MATLAB where G1(s) = 4, G2(s) = 1/(s+2) and H(s) = 5s.Solution: Type the following in the MATLAB command line: G1 = tf([0 4],[0 1]); G2 = tf([0 1],[1 2]); H = tf([5 0],[0 1]); SYS = feedback(G1*G2,H) This produces the following output on the command window (check this result): Transfer function: 4 ——-21 s + 2 Exercise: Compute the closed-loop transfer function of the following system using MATLAB. R(s) +_ 1 s +1 14 s+2 s+3 Y(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 6. Time Response Analysis with MATLABAfter entering the transfer function of a LTI system, we can compute and plot the time response of this system due to different input stimuli in MATLAB. In particular, we will consider the step response, the impulse response, the ramp response, and responses to other simple inputs. 6. 1. Step response To plot the unit-step response of the LTI system SYS=tf(num,den) in MATLAB, we use the command step(SYS). We can also enter the row vectors of the numerator and denominator coefficients of the transfer function directly into the step function: step(num,den).Example: Plot the unit-step response of the following system in MATLAB: Y (s) 2s + 10 =2 R (s) s + 5s + 4 Solution: Step Response 2. 5 num = [0 2 10]; den = [1 5 4]; SYS = tf(num,den); step(SYS) Amplitude 2 or directly: step(num,den) 1. 5 1 MATLAB will then produce the following plot on the screen. Confirm this plot yourself. 0. 5 0 0 1 2 3 Time (sec. ) 4 5 For a step input of magnitude other than unity, for example K, simply multiply the transfer function SY S by the constant K by typing step(K*SYS). For example, to plot the response due to a step input of magnitude 5, we type step(5*SYS).Notice in the previous example that that time axis was scaled automatically by MATLAB. You can specify a different time range for evaluating the output response. This is done by first defining the required time range by typing: t = 0:0. 1:10; % Time axis from 0 sec to 10 sec in steps of 0. 1 sec and then introducing this time range in the step function as follows: step(SYS,t) % Plot the step response for the given time range, t This produces the following plot for the same example above. 15 6 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) _______________________________________________________________________________ Step Response 2. 5 Amplitude 2 1. 5 1 0. 5 0 0 2 4 6 8 10 Time (sec. ) You can also use the step function to plot the step responses of multiple LTI systems SYS1, SYS2, †¦ etc. on a single figure in MATLAB by typing: st ep(SYS1,SYS2,†¦ ) 6. 2. Impulse response The unit-impulse response of a control system SYS=tf(num,den) may be plotted in MATLAB using the function impulse(SYS). Example: Plot the unit-impulse response of the following system in MATLAB: Y(s) 5 = R (s) 2s + 10 Solution: Impulse Response um = [0 5]; den = [2 10]; SYS = tf(num,den); impulse(SYS) 2. 5 2 impulse(num,den) Amplitude or directly 1. 5 1 This will produce the following output on the screen. Is that what you would expect? 0. 5 0 0 0. 2 0. 4 0. 6 Time (sec. ) 16 0. 8 1 1. 2 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 6. 3. Ramp response There is no ramp command in MATLAB. To obtain the unit ramp response of the transfer function G(s): multiply G(s) by 1/s, and use the resulting function in the step command.The step command will further multiply the transfer function by 1/s to make the input 1/s2 i. e. Laplace transform of a un it-ramp input. For example, consider the system: Y(s) 1 =2 R (s) s + s + 1 With a unit-ramp input, R(s) = 1/s2, the output can be written in the form: Y(s) = 1 1 1 R (s) = 2 ? s + s +1 (s + s + 1)s s 2 1 ? ?1 =? 3 2 ?s + s + s ? s which is equivalent to multiplying by 1/s and then working out the step response. To plot the unitramp response of this system, we enter the numerator and denominator coefficients of the term in square brackets into MATLAB: num = [0 0 0 1]; en = [1 1 1 0]; and use the step command: step(num,den) The unit ramp response will be plotted by MATLAB as shown below. Step Response 12 10 Amplitude 8 6 4 2 0 0 2 4 6 Time (sec. ) 17 8 10 12 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 6. 4. Arbitrary response To obtain the time response of the LTI system SYS=tf(num,den) to an arbitrary input (e. g. exponential function, sinusoidal function .. etc. ), we can use the lsim command (stands for ‘linear simulation') as follows: lsim(SYS,r,t) or lsim(num,den,r,t) here num and den are the row vectors of the numerator and denominator coefficients of the transfer function, r is the input time function, and t is the time range over which r is defined. Example: Use MATLAB to obtain the output time response of the transfer function: Y(s) 2 = R (s) s + 3 when the input r is given by r = e-t. Solution: Start by entering the row vectors of the numerator and denominator coefficients in MATLAB: num = [0 2]; den = [1 3]; Then specify the required time range and define the input function, r, over this time: t = 0:0. 1:6; r = exp(-t); % Time range from 0 to 6 sec in steps of 0. 1 sec Input time function Enter the above information into the lsim function by typing: lsim(num,den,r,t) This would produce the following plot on the screen. Linear Simulation Results 0. 4 0. 35 Amplitude 0. 3 0. 25 0. 2 0. 15 0. 1 0. 05 0 0 1 2 3 Time (sec. ) 18 4 5 6 ECM2105 – C ontrol Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ TUTORIAL PROBLEM SHEET 3 1. Find the transfer function between the input force u(t) and the output displacement y(t) for the system shown below. y(t) b1 u(t) m b2 where b1 and b2 are the frictional coefficients.For b1 = 0. 5 N-s/m, b2 = 1. 5 N-s/m, m = 10 kg and u(t) is a unit-impulse function, what is the response y(t)? Check and plot the response with MATLAB. 2. For the following circuit, find the transfer function between the output voltage across the inductor y(t), and the input voltage u(t). R u(t) L y(t) For R = 1 ? , L = 0. 1 H, and u(t) is a unit-step function, what is the response y(t)? Check and plot the result using MATLAB. 3. Find the transfer function of the electrical circuit shown below. R L u(t) y(t) C For R = 1 ? , L = 0. 5 H, C = 0. 5 F, and a unit step input u(t) with zero initial conditions, compute y(t).Sketch the time function y(t) and pl ot it with MATLAB. 19 ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 4. In the mechanical system shown in the figure below, m is the mass, k is the spring constant, b is the friction constant, u(t) is the external applied force and y(t) is the corresponding displacement. Find the transfer function of this system. k u(t) m For m = 1 kg, k = 1 kg/s2, b = 0. 5 kg/s, and a step input u(t) = 2 N, compute the response y(t) and plot it with MATLAB. b y(t) 5.Write down the transfer function Y(s)/R(s) of the following block diagram. R(s) Y(s) K +_ G(s) a) For G(s) = 1/(s + 10) and K = 10, determine the closed loop transfer function with MATLAB. b) For K = 1, 5, 10, and 100, plot y(t) on the same window for a unit-step input r(t) with MATLAB, respectively. Comment on the results. c) Repeat (b) with a unit-impulse input r(t). 6. Find the closed loop transfer function for the following diagram. R(s) E(s) Y(s) G(s) +_ F(s) H(s) a) For G(s) = 8/(s2 + 7s + 10) and H(s) = s+2, determine the closed loop transfer function with MATLAB. ) Plot y(t) for a unit-step input r(t) with MATLAB. 7. Determine the transfer function of the following diagram. Check your answer with MATLAB. _ R(s) +_ s s + + 1/s s 20 1/s Y(s) ECM2105 – Control Engineering Dr Mustafa M Aziz (2010) ________________________________________________________________________________ 8. Determine the transfer function of the following diagram. R(s) +_ +_ 50 s +1 Y(s) s 2/s 1/s2 2 +_ a) Check you result with MATLAB. b) Plot y(t) for a unit-impulse input r(t) with MATLAB. 9. Determine the total output Y(s) for the following system. D(s)