In the context of environmental toxicology, what does 'heavy metal' Essay

In the context of environmental toxicology, what does 'heavy metal' actually mean - Essay Example However, this assumption has no fundamental basis on the available toxicological or chemical data. Legal regulations have specified an inventory of heavy metals applied in various situations. There is no definition that is authoritative in literatures that are relevant. There is a tendency of assuming that all heavy metals in conjunction with their compounds have properties that are highly eco-toxic or toxic. Arguably, this assumption has no prove in toxicological or chemical data. Hence, the term heavy metal is misleading and meaningless. Furthermore, the word metal is also misused in legislation and toxicological data. In these literatures it is used to mean a metal that is pure and the entire species chemical in which it occurs. This is untrue because, all pure metals can not exhibit similar toxicological and chemical properties. For purposes of avoiding the term heavy metal, there is need for reclassification of the periodic table as people refer to the term heavy metal as mislea ding and meaningless. The change in classification should mirror individuals understanding of toxicity chemical basis and provide room for the prediction of toxic impacts. Classification of heavy metals The increased worry on environmental pollution reduction has triggered the continued literature and research on heavy metals toxicology (Rabajczyk et al., 2011). Heavy metals emit their toxic substances through the formation of complexes with compounds that are organic. These eventually results to formation of modified biological molecules that lose their functioning ability. The outcome is affected cell malfunction or death. The most common heavy metals that form organic compounds that are complex are such as oxygen, sulfur and nitrogen. Classification of heavy metals is done depending on which class it lies. For example class A belong to the hard metals, class be identifies soft metals and lastly we have the intermediate metals. Heavy metals such as Mercury, Lead and cadmium fall u nder class B which represents soft metals. On the other hand chromium is an intermediate metal. The classification of these metals varies depending on their chemical formula. How Heavy Metal Occurs in the Environment Through causes that are both anthropogenic and natural, heavy metals find their way into the environment. The major emission causes are human sources such as mining operations. Heavy metals are exposed into the environment in forms that are both inorganic and organic. Anthropogenic sources of emissions occur from both point and non-point sources such as industrial areas such as present and previous sites of mining, smelters and foundries and by-products and traffics combustion. The pollution of the environment by heavy metals is acute in mining locations and it decreases as the distance widens from those mining sites. The heavy metals are often leached into the soil and ground water. Those in sloppy areas find their way into the water bodies through surface runoff. The heavy metals eventually attach themselves to the sediments whilst some leak into the waters underground resulting to their contamination. Underground and surface water sources heavy metal contamination leads to soil pollution. Exposure of the heavy metals to air and rain is via dumping on the surface soil. Pollution of Agricultural soils results to the uptake of the heavy metals by plants resulting to their accumulation in the plant tissues. These consequently happen to those marine animals and domestic

Problems of Conducting Research Into the Causes of Stress Essay Example for Free

Problems of Conducting Research Into the Causes of Stress Essay One problem when conducting research into the causes of stress is the generalisation of the sample, if the sample is restricted; this has limitations in terms of generalising the results to the total population. In the study by Johansson, a sample of only 24 workers was used and from a specific job type. This sample is unreflective of all job types and is too small to be applicable to the general population. Conclusions made may only be relevant to this sample. However it could be argued that the factors that cause stress in jobs such as deadlines and the dependence of others on you are common in all types of jobs and therefore using a sample of the specific job type becomes less restricted and applicable to other people in jobs with common stressors. A second problem when conducting research into causes of stress is the validity of measurements. Validity refers to whether the results measure what they are supposed to measure and this is often affected by the research method. The self report method is often questioned in terms of validity as participants have the ability to give socially desirable answers and steer away from the truth. In the study by Kanner, questionnaires were posted out to participants and a Hassles and uplifts scale was asked to be completed every month for 9 months and the Berkman life events scale after 10 months. This study, due to the use of self report lacks in validity, as researches are unsure as to whether data obtained reflects the true opinions of participants, which is an issue when trying to apply to everyday life. However the self report method is useful, despite it lacking in validity. It gives participants the freedom to write about their own subjective feelings and due to stress being individually perceived differently, it is useful in tailoring treatment to individuals to meet their needs. A third problem is reductionism, studies often reduce many factors that cause an individual stress to one factor, such as in the case of Johansson study, it was concluded work was the source of stress. However individual factors such as personality could play a role, researchers do not know that stress prone individuals are more likely to be in a high risk job. By failing to take into account other factors, resources and time may be used in the wrong area. However reductionism is useful as it does pinpoint an area that causes stress and allows in-depth research to be carried out to help participants.

Dead Poet society :: essays research papers

â€Å"I want to make them free thinkers† says Mr Keating to Mr McAllister. This essay will define the meaning of â€Å"free thinker†, its importance to the young men of Mr Keating's class, the meaning of Mr Keating's statement and finally the different impacts that this new way of thinking has on the boys. A â€Å"Freethinker† as defined by The Macquarie Dictionary is â€Å"someone who forms their opinions independently of authority or tradition, especially in matters of religion†. Therefore a free thinker is someone who can produce ideas for themselves and is not solely reliant on the thoughts and actions of others to predetermine their life path. To pass from childhood to adulthood is usually an adjustment from following the rules and regulations of figures in society such as parents and teachers to making conscience independent decisions about future actions based on one's own beliefs and ideas. Often this pathway is a difficult voyage and those who go through are usually aided by mentors that they can get guidance from. Mr Keating in the Dead Poets Society was such a mentor for a group of confused young men who had been used to convention and stifling of creativity and freethinking all of their time at Welton Preparatory School for Boys. What Mr Keating means by â€Å"i want to make them free thinkers† is that he wants the young men of his English class all to live a fulfilled life and to do this they must stop following the set structure like a herd of sheep following one and another For example in the movie â€Å"Dead Poet Society† when Mr Keating gets all the boys within his English class to ripe out the introduction entitled â€Å"Understanding Poetry† by Dr. J. Evans Pritchard, Ph.D. Evans explains Poetry by being able to be graded on a graph to determan if a poem is good or not. Mr Keating gets the boys to understand that you can not tell if a poem is good or not by a graph but by how much it means to you and the way it makes you feel. This is becoming a free thinker not using a set structure but actually understanding and appreciating it. He also believes that you can not set an age where free thinking should begin and it should be something that happens all throughout life. For the boys t o learn and accomplish the things that Mr Keating wants them to within his class, they must think with there minds and not using a book.

Used Cooking Oil as Candle

Used Cooking Oil as an Additive Component of Candle Abstract The study aims to produce a low-priced, high-quality candle by using used cooking oil as a major component. The following candle compositions were used: 100 percent paraffin wax; 90 percent paraffin and 10 percent oil; 80 percent paraffin and 20 percent oil; 70 percent paraffin and 30 percent oil; 60 percent paraffin and 40 percent oil; 50 percent paraffin and 50 percent oil. The firmness, texture, and light intensity of the candles were tested and compared. Results of the tests showed that the candle made from 100 percent paraffin wax had the lowest melting rate, lowest amount of melted candle, and a light intensity of 100 candelas (cd). The 90:10 preparation had the next lowest melting rate and amount of melted candle. The other preparations ranked according to the proportion of used cooking oil in the candle, with the 50:50 preparation performing least comparably with the 100 percent paraffin wax candle. Introduction Today, candles are made not only for lighting purposes but for many other uses such as home decor, novelty collections, as fixtures for big occasions (weddings, baptismals, etc. ), and as scented varieties for aromatherapy. Candles are made from different types of waxes and oils. Cooking oil is a major kitchen item in Filipino households. It is also used substantially in fast-food outlets, where it is used in different stages of food preparations. Ordinarily, used cooking oil is discarded. This waste oil pollutes and clogs canals and sewerage systems

Midnight in the Garden of Good and Evil Essay

Question 8: Danny Hansford is only one of the many people whose violent deaths we learn about in the course of Midnight in the Garden of Good and Evil. Judging by their stories, what does Savannah (or Savannah society) deem grounds for murder? Why are so few of Jim William’s friends disturbed by the charges against him? Given the casualness with which Savannahians greet the Hansford case, why are they so shocked by the news [p. 333] that their city has been declared the murder capital of the United States? *Answer: In the beginning, Jim goes over the deaths that have happened in Savannah; while the others are blinded by their selfishness. For example: One of the stories known in the Savannah’s society is the death of the judge’s son. It all started when the son of the judge had an imitate relationship with the gangster’s girl; sooner or later the alpha finds out about these rendezvous. As a result, the gangster shot the boy and took his â€Å"manhood† with him. The following days, the young fellow recovered swiftly with his testicles by his side but unfortunately the doctors couldn’t repair a broken heart. At last, his misery ended when he collapsed on the front porch, breathing his last breath as Death took his life. The death of this boy was disregarded by the Savannah’s society; showing no empathy/ emotions towards his death. The few friends of Jim were disturbed because rumors have it that Jim was homosexual and had a sexual relationship with Danny Hansford (***Remember, the Savannah’s society was old-fashioned and didn’t believe in these kinds of relations. ) The Savannahians were shocked about their murder rate because in their minds, they thought they had an outlined of 1,000 untroubled suburbanites not sufficient to raise their murder rate. They were positive that the statistics was a mistake. Savannah had 54 murders/ or 22. 6 murders per 100,000 Savannah’s society blamed the deaths on the African Americans because 91% of their population was blacks. Works Cited Berendt, John. Midnight in the Garden of Good and Evil. Random House, 1994.

Slow Drivers Essay Example

Slow Drivers Essay Example Slow Drivers Essay Slow Drivers Essay Have you ever been trapped behind a slow driver when you’re already late for something really important? Nine times out of ten the driver was an elderly person, who has no business being on the road. How many times have you asked yourself, â€Å"What is this person doing? † And how many times have you passed this person, and come to find out it’s a grandma or grandpa? If there is a person who can barely see over the steering wheel, has 3-inch thick glasses, and has poor motor skills, they should not be operating a vehicle. These are the older generation, so to speak, of people that should not be driving. I’m not sure when a human being should have their driving privileges suspended, but I’m guessing around age 75 to 90 years old, depending on the case. Not all elderly drivers are a danger to our community, but there are more so than not. There are these aged drivers who are driving so slow and erratic, it’s causing frequent car accidents, not to mention impatient attitudes. It’s one thing to be driving 45 miles an hour on the freeway, but another to drive in two lanes at the same time. Pick a lane and stay there! It is a known fact that mature adults start to lose their motor skills and have slower reaction times than younger drivers. These fogeys are not all to blame. It’s the people who are testing them in their driver’s license exams. The driving instructors probably feel sorry for them and are perhaps maybe â€Å"respecting their elders†. Doesn’t anybody tell these old folks that they are driving like molasses and irritating people? I’m sure their children do, and others drivers do, using the one finger salute, but I’m sure they pay no attention to those â€Å"darn kids! †

The Characteristics of a Compelling Introduction

The Characteristics of a Compelling Introduction An introduction is the opening of an essay or speech, which typically identifies the topic, arouses interest, and prepares the audience for the development of the thesis. Also called an  opening, a lead,  or an introductory paragraph. For an introduction to be effective, says Brendan Hennessy, it should  persuade readers that what you have to say is worth close attention. Etymology From the Latin, to bring in. Examples and Observations In addition to appealing to readers and helping them to anticipate tone and substance, the opening passage can also help readers read by helping them to anticipate the structure of what will follow. In classical rhetoric, this was called the division or partition because it indicates how the piece of writing will be divided into parts. Methods of Introducing an EssayHere are a few possible ways to open an essay effectively:State your central idea, or thesis, perhaps showing why you care about it.Present startling facts about your subject.Tell an illustrative anecdote.Give background information that will help your reader understand your subject, or see why it is important.Begin with an arresting quotation.Ask a challenging question. (In your essay, youll go on to answer it.)Example of Introductory Paragraph in an Essay Bill Clinton loves to shop. On a March day in an elegant crafts store in Lima, the Peruvian capital, he hunted for presents for his wife and the women on his staff back home. He had given a speech at a university earlier and just came from a ceremony kicking off a program to help impoverished Peruvians. Now he was eyeing a necklace with a green stone amulet. Four Goals of IntroductionsAn effective introduction has four basic goals:Catch the audiences attention and focus it on your topic.Motivate the audience to listen by pointing out how your topic will benefit them.Establish credibility and rapport with your audience by creating a common bond and letting them know about your expertise and experience with the topic.Present your thesis statement, which includes clarification of your central idea and main points.Examples of an Introduction in a Speech The first thing I would like to say is ‘thank you.’ Not only has Harvard given me an extraordinary honour, but the weeks of fear and nausea I have endured at the thought of giving this commencement address have made me lose weight. A win-win situation! Now all I have to do is take deep breaths, squint at the red banners, and convince myself that I am at the world’s largest Gryffindor reunion. (J.K Rowling) Quintilian on the Appropriate Time to Compose an Introduction (or Exordium) ï » ¿I do not, on these accounts, agree with those who think that the exordium is to be written last; for though it is proper that our materials should be collected, and that we should settle what effect is to be produced by each particular, before we begin to speak or write, yet we ought certainly to begin with that which is naturally first. No man begins to paint a portrait, or mold a statue, with the feet; nor does any art find its completion where the commencement ought to be. Else what will be the case if we have no time to write our speech? Will not so preposterous a practice disappoint us? The orators materials are, therefore, to be first contemplated in the order in which we direct, and then to be written in the order in which he is to deliver them. Pronunciation in-tre-DUK-shun Sources Brendan Hennessy, How To Write Coursework and Exam Essays, How To Books 2010.Richard Coe,  Form and Substance: An Advanced Rhetoric. Wiley, 1981X.J. Kennedy et al.,  The Bedford Reader. Bedford/St. Martins, 2000Introduction to Its Not About Bill, by Peter Baker.  The New York Times Magazine, May 31, 2009Cheryl Hamilton,  Essentials of Public Speaking, 5th ed. Wadsworth, 2012J.K. Rowling, commencement address at Harvard University, June 2008Quintilian,  Institutes of Oratory, 95 AD