Industrial Hygiene Essay Example | Topics and Well Written Essays - 250 words

Industrial Hygiene - Essay Example Also, the United States Code defines toxin as a deadly and poisonous substance that is either produced by plants, animals, or by artificial processes (US Code, 18, 2008). Toxins are classified into two main groups: bio-toxins and environmental toxins. Bio-toxins are toxic materials that unequivocally substantiate biological origin. Common types of bio-toxins are systemic toxins, neurotoxin, cytotoxin, and hemotoxin. On the other hand, environmental toxins are those that include man-made poisons. Most common types of environmental toxins are neurotoxic shellfish poisoning, and toxic triggers like pesticides and monosodium glutamate. Exposure to toxins does not necessarily cause disease. The amount or dose of the toxic material and length of time at which a person is exposed to the toxin determine the risk of developing serious diseases (CCOHS, 2009). Parkinson’s disease is considered to be caused by exposure to toxins. However, case studies show that there is no direct correlation between developing the disease and exposure to chemicals. In fact, it â€Å"involves combination of genetic and environmental risk factors, which include exposure to manganese, lead, etc. (Schmidt,

Genotoxicity of Endodontic Irrigants and Medicaments

Genotoxicity of Endodontic Irrigants and Medicaments Abstract Genotoxicity describes a deleterious action on a cells genetic material affecting its integrity. This includes both certain chemical compounds and certain types of radiation. Genotoxic substances are all those with affinity to interact with DNA which is not proof of their dangerousness to humans, but does render them potentially mutagenic or carcinogenic. This review will address the genotoxicity of endodontic irrigants, medicaments, and sealers. It has been postulated that exposure of living tissues to cytotoxic agents can result in chronic cell injury, compensatory cell proliferation, hyperplasia, irritation, degeneration or tissue necrosis (1) and ultimately tumor development (2, 3). It is likely that proliferation may increase the risk of mutations within target cells and also be important in selective clonal expansion of exogenously or endogenously initiated cells from pre-neoplastic foci and eventually tumors (2). Thus, the DNA damage may diminish the self-repairing potential of tissue (4). In light of these considerations, genotoxicity and cytotoxicity assays gained widespread acceptance as an important and useful indicator of carcinogenicity. Definition of genotoxicity In genetics, genotoxicity describes a deleterious action on a cells genetic material affecting its integrity. This includes both certain chemical compounds and certain types of radiation. Genotoxic substances are all those with affinity to interact with DNA which is not proof of their dangerousness to humans, but does render them potentially mutagenic or carcinogenic (5). Genotoxicity of root canal irrigants Sodium hypochlorite Sodium hypochlorite (NaOCl) is recommended as the main endodontic irrigant because of its ability to dissolve organic matter together with its broad antimicrobial action (6). NaOCl is commercially available as aqueous solutions with concentrations ranging from 1% to 15% and having an alkaline pH with values around 11 (7). Sodium hypochlorite has a wide range activity against both Gram positive and Gram negative bacteria. It is the strongest antifungal agent among root canal irrigations and medications. Furthermore, it is the only root canal irrigant that can destroy the microbial biofilm effectively (6, 7). Hamaguchi and Tsyutsui (8) showed that NaOCl was not genotoxic to mamalian cells. Hagiwara et al. (9) showed that sodium hypochlorite induced chromosome aberrations in Syrian hamster embryo (SHE) cells when treated in the presence of exogenous metabolic activation. Aubut et al. (10) revealed that neutralizing a 2.5% NaOCl solution did not induce any genotoxic effect. Marins et al. (11) showed that NaOCl did not induce any genotoxic effect. Chlorhexidine CHX is a synthetic cationic bis-guanide that consists of two symmetric 4-cholorophenyl rings and two biguanide groups connected by a central hexamethylene chain. CHX is a positively charged hydrophobic and lipophilic molecule that interacts with phospholipids and lipopolysaccharides on the cell membrane of bacteria and then enters the cell through some type of active or passive transport mechanism (12). Its efficacy is due to the interaction of the positive charge of the molecule and the negatively charged phosphate groups on microbial cell walls (12), thereby altering the cells osmotic equilibrium. This increases the permeability of the cell wall, which allows the CHX molecule to penetrate into the bacteria. CHX is a base and is stable as a salt. The most common oral preparation, chlorhexidine gluconate, is water-soluble and at physiologic pH, it readily dissociates and releases the positively charged chlorhexidine component (12). At 0.2% concentration, due to the leakage of low mol ecular weight substances(potassium and phosphorous) from the bacterial cell wall, CHX is bacteriostatic. On the other hand, at 2% concentration, CHX is bactericidal, as precipitation of the cytoplasmic contents occurs and resulting in cell death (13). Ribeiro et al. (14) revealed that chlorhexidine digluconate is able to induce primary DNA damage in leukocytes and in oral mucosal cells, but no chromosome breakage or loss in erythrocytes. Another study indicated that CHX in 0.01% and 1% concentrations did not induce DNA damage. Yeung et al. (15) stated that potential genotoxicity and tissue damage when extruded into the periradicular tissue and at higher concentrations should be considered during periodontal and endodontic practice. Li et al. (16) revealed that CHX-induced genotoxicity on macrophages may be via reactive oxygen species generation. MTAD BioPure (Dentsply, Tulsa Dental, Tulsa, OK, USA), otherwise known as MTAD, was introduced by Torabinejad et al. in 2003 (17). It is composed of 3% doxycycline, 4.25% citric acid and a detergent (0.5% Polysorbate 80) (17). Marins et al. (18) assessed the genotoxicity of MTAD using single cell gel (comet) assay. Results showed that the BioPure MTAD was able to promote DNA breakage in CHO cells only at the highest concentration tested as well as to induce significant increase in tail moment at all tested concentrations in murine fibroblasts. Another study revealed that MTAD did not cause cell death, but presented genotoxic effects (19). EDTA EDTA (Ethylenediaminetetraacetic acid) refers to the chelating agent with the formula (HO2CCH2)2NCH2CH2N(CH2CO2H)2. This amino acid is widely used to sequester di- and tri-valent metal ions. EDTA binds to metals via four carboxylate and two amine groups. EDTA forms specially strong complexes with Mn(II), Cu(II), Fe(III), and Co(III). EDTA is mostly synthesised from 1,2-diaminoethane (ethylenediamine), formaldehyde (methanal), water and sodium cyanide. This yields the tetra sodium salt, which can be converted into the acidic forms by acidification (20, 21). EDTA is a polyamino carboxylic acid and a colourless, water-soluble solid. It is widely used to dissolve limescale. Its usefulness arises due to its role as a hexadentate ligand and chelating agent, i.e. its ability to sequester metalions such as Ca2+ and Fe3+. After being bound by EDTA, metal ions remain in solution but exhibit diminished reactivity. EDTA is produced as several salts, notably disodium EDTA and calcium disodium EDTA. The compound was first described in 1935 by Ferdinand Munz, who prepared the compound from ethylenediamine and chloroacetic acid (22). Today, EDTA is mainly synthesised from ethylenediamine (1,2-diaminoethane), formaldehyde, and sodium cyanide (22). EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. EDTA demineralizes dentine to a depth of 20–30 ÃŽ ¼m in 5 min (23). According to Heindorff et al. (24) EDTA influences chromosome breakage by mutagenic agents. In particular, when applied in combination with chemical mutagens, EDTA enhances mutagen-induced aberration frequencies. Furthermore, they reported that EDTA affects the inhibition of DNA synthesis in primary cultures of mammalian cells. This may be due to impairment of enzymes involved in DNA replication. Using single cell gel (Comet)assay, Marins et al. (25) showed that EDTA did not produce genotoxic effects. Iodine potassium iodide (IKI) Iodine was first discovered in seaweed in the early 1800s. Although its exact mode of action is not fully known, it is thought to induce cell death nonspecifically due to the oxidizing effects of free iodine on SH-OH- and NH groups of amino acids and on double bonds of unsaturated fatty acids. Iodine is highly efficient microbicide to a wide variety of bacterial, fungal and viral infections (26). Potassium iodide (KI) is a compound made of 76% of iodine and 23% of the alkali metal potassium by weight. KI is prepared by reacting iodine with a hot solution of potassium hydroxide, the product being subsequently reduced to iodide by heating the dry reaction mixture with carbon. Another form of iodine compounds is IKI. The solution can be prepared by mixing 2 g of iodine in 4 g of KI; this mixture then is dissolved in 94 ml of distilled water (26). Poul et al. (27) assessed the genotoxic effects of potassium iodate in vitro using the alkaline comet assay and the cytokinesis-block micronucleus assay on CHO cells. Results showed that potassium chlorate as well as potassium iodide, bromide and chloride did not induced DNA damage in the alkaline comet assay for doses up to 10 mM. In another study, Hikiba et al. (28) assessed the effect of iodine and iodoform on chromosome aberrations using Syrian hamster embryo (SHE) cells and found that iodine induced chromosome aberrations and iodoform induced no genotoxicity. Using the comet assay and chromosome aberration test to characterize the genotoxic potency of povidone-iodine within 4 h of contact with CHO-K1 cells, Muller et al. (29) found no chromosomal damage. In another study, Hedayati et al. (30) showed that incubation of lymphocytes with (131)I induced genotoxicity, which was reflected by an increase in micronuclei frequency. Genotoxicity of intracanal medicaments Calcium hydroxide Calcium hydroxide [Ca(OH)2 ] was originally introduced to the field of endodontics by Herman in 1920 as a pulp-capping agent. It is a white odorless powder with the formula Ca(OH)2, and a molecular weight of 74.08 (31). Calcium hydroxide has low solubility in water (about 1.2 gL-1 at 25 C), which decreases as the temperature rises. The dissociation coefficient of Ca(OH)2 (0.17) permits a slow, controlled release of both calcium and hydroxyl ions. The low solubility is a good clinical characteristic as a long period is necessary before it becomes soluble in tissue fluids when in direct contact with vital tissues (32). It has a high pH (about 12.5-12.8), is insoluble in alcohol and is chemically classified as a strong base, it main actions come from the ionic dissociation of Ca2+ and OH- ions and their effect on vital tissues, generating the induction of hard tissue deposition and being antibacterial. Ca(OH)2 dissociates into calcium and hydroxyl ions on contact with aqueous fluids. Ca (OH)2 in water has a thixotropic behavior (33). According to Ribeiro et al. (34) calcium hydroxide do not promote DNA damage in mammalian cells. In another study, Ribeiro et al. (35) revealed that calcium hydroxide was not able to modulate alkylation-induced genotoxicity or oxidative DNA damage as depicted by the single cell gel (comet) assay. MTA MTA is a mixture of a refined Portland cement and bismuth oxide and trace amounts of SiO2, CaO, MgO, K2SO4, and Na2SO4 (36). Portland cement is a mixture of dicalcium silicate, tricalcium silicate, tricalcium aluminate, gypsum, and tetracalcium aluminoferrite (37). Gypsum, and to a lesser extent, tetracalcium aluminoferrite are important determinant of setting time (37). MTA contains fewer toxic heavy metals, has a longer working time, and have undergone additional processing/purification than regular Portland cements (36). The MTA powder is mixed with supplied sterile water in a 3:1 powder/liquid ratio and it is recommended that a moist cotton pellet be temporarily placed in direct contact with the material and left until a follow-up appointment (38). Upon hydration, MTA materials form a colloidal gel that solidifies to a hard structure in approximately 3–4h, with moisture from the surrounding tissues purportedly assisting the setting reaction (38). Hydrated MTA has an initia l pH of 10.2, which rises to 12.5 three hours after mixing (39). Using single cell gel (comet) assay, Ribeiro et al. (40) detected no DNA damage after a treatment of cells by MTA and Portland cements for concentrations up to 1000  µ/ml. In another study, Ribeiro et al.(41) demonstrated that regular and white MTA did not produce genotoxic effects at 1 to 1000  µgmL-1 FOR 3 H AT 37 C. Another study using Chinese hamster ovary (CHO) cells indicated that that MTA and Portland cements are not genotoxins and are not able to induce cellular death (42). Braz et al. (43) assessed the genotoxic effects of MTA and Portland cements in peripheral lymphocytes from 10 volunteers by the alkaline single cell gel (comet) assay. Findings failed to detect the presence of DNA damage after a treatment of peripheral lymphocytes by MTA and Portland cements for concentrations up to 1000 mug mL(-1). Camargo et al. (44) revealed that regular and white MTA preparations did not negatively influence cell survival or reactive oxygen species production. Ding et al. (45) show ed that MTA and calcium silicate possessed no genotoxic effect. According to Zeferino et al. (46) MTA as well as Portland cement+15% bismuth oxide were not genotoxic. Genotoxicity of root canal sealers For assessment of the genotoxic potential of any material, it is recommended to perform a series of in vitro tests. At least two assays, investigating different endpoints, shall use mammalian cells. For cytotoxic and bactericidal compounds, as many endodontic  sealers appear to be, care must be taken in the test set up: For a proper evaluation the selected test concentrations used for genotoxic effects must be below the concentrations where toxic effects are found (47). Ørstavik and Hongslo (48) showed that extracts of a synthetic polymer material, based on epoxy-bis-phenol A, induced mutations in Salmonella typhimurium TA 100 as did extracts of the epoxy-bis-phenol A resin alone. Formaldehyde, an active ingredient from one of the ZnO-based materials, induced mutations in both Salmonella typhimurium TA 98 and TA 100. The mutagenic activity of formaldehyde as well as of the epoxy material was reduced in the presence of rat liver microsomes. Schwikl et al. (49) showed that eluates of mixed AH26 were mutagenic, and their genotoxicity was strongly depended on the setting time. The number of mutants after exposure to eluates of unset AH26 was enhanced approximately 7- to 10-fold. However, the mutagenic activity of the mixed material was clearly reduced after a setting time of 1 wk. Physiological saline eluates of the mixed AH26 were not found to be mutagenic. Dimethyl sulfoxide eluates of the liquid component of AH26 elicited mutagenic effects similar to the freshly mixed material; eluates made in physiological saline were barely mutagenic at a 10-fold higher concentration. Leyhausen et al. (50) showed that AH-Plus revealed no genotoxicity and mutagenicity. Epoxy-based sealers are also mutagenic in mammalian cell mutation assays. Ersev et al. (51) showed that silver-free AH26 set for 24 h were weakly mutagenic in Salmonella typhimurium TA100. They further showed that silver-free AH26 might contain small amounts of two mutagenic substances: bisphenol A diglycidyl ether and formaldehyde. Tai et al. (52) revealed that root canal sealers containing formaldehyde and bisphenol A diglyether proved to be not only cytotoxic but also genotoxic. Miletic et al. (53) found no mutagenicity found for AH26 and AH Plus sealers on human lymphocytes in highly controlled conditions in vitro. Formaldehyde is released from some epoxy-based sealers with a maximum after 2 days, even though the amount is much less than that of paraformaldehyde containing zinc oxide-eugenol sealers (54). It was believed that the leakage of formaldehyde and bisphenol- A diglycidyl ether from the epoxy-sealers contributed to the mutagenic effects (49, 55). Formaldehyde is classified as a carcinogen in animals, whereas there exists only limited evidence for carcinogenic effects in man (56). There is also limited evidence for animal carcinogenicity from bisphenol-A diglycidyl ether and no adequate data for the evaluation of human cancer risk for this compound (57). Considering the limited exposure of these compounds from endodontic epoxy sealers and the lack of definitive assessment by the IARC, it seems unlikely that such sealers contribute to an increased risk of cancer in patients. However, the high level of paraformaldehyde in zinc oxide-eugenol. Using Comet assay, Huang et al. () showed that the zinc oxide eugenol-based sealers  (Canals, Canals-N, and Tubilseal) did not always cause a dose-dependent increase in genotoxicity. The resin-based sealers (Topseal, AH 26, and AH Plus) caused a dose-dependent increase in genotoxicity, but no such effect was seen with the calcium hydroxide-based sealer (Sealapex) (47).

biological species concept :: essays research papers fc

Biological Species Concept (BSC) What are biological species? At first glance, this seems like an easy question to answer. Homo sapiens is a species, and so is Canis familaris (dog). Many species can be easily distinguished. When we turn to the technical literature on species, the nature of species becomes much less clear. Biologists offer a dozen definitions of the term "species". These definitions are not fringe accounts of species but prominent definitions in the current biological literature. Philosophers also disagree on the nature of species. Here the concern is the ontological status of species. Some philosophers believe that species are natural kinds. Others maintain that species are particulars or individuals. The concept of species plays an important role both in and outside of biology. Because of the important role of this concept, many biologists proposed definitions for this concept. Over the last few decades, the Biological Species Concept (BSC) has become predominately the dominant species definition used in biology. This concept defines a species as a reproductive community. This though has had much refinement through the years. The earliest precursor to the concept is in Du Rietz (1930) then later Dobzhansky added to this definition in 1937. But even after this the definition was highly restrictive, the definition of a species that is accepted as the Biological Species Concept was founded by Ernst Mayr; â€Å"...groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups†. However, this is a definition on what happens in nature. Mayr later amended this definition to include an ecological component; â€Å"... a reproductive community of populations (reproductively isolated from others) that occupies a specific niche in nature. The BSC is greatly accepted among vertebrate zoologists and en tomologists. Two reasons account for this addition to the definition of Biological Species Concept. Firstly, these are the groups that the authors of the BSC worked with (Mayr is an Ornithologist & Dobzhansky has worked mainly with Drosophila). More importantly, Sexual reproduction is the predominate form of reproduction in these groups. It is not coincidental that the BSC is less widely used amongst botanists. Terrestrial plants exhibit much greater diversity in their mode of reproduction than vertebrates and insects. There have been many criticisms of the BSC in its theoretical validity and practical utility. For example, the application of the BSC to a number of groups is problematic because of interspecific hybridization between clearly delimited species.

Coral Bleaching Proposal

Coral reefs deliver ecosystem services to tourism, fisheries and shoreline protection and often called â€Å"rainforests of the sea†. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. Coral reefs grow best in warm, shallow, clear, sunny and agitated waters. However, coral reefs are fragile ecosystems, partly because they are very sensitive to water temperature.They are under threat from climate change, oceanic acidification, blast fishing, cyanide fishing for aquarium fish, overuse of reef resources, and harmful land-use practices, including urban and agricultural runoff and water pollution, which can harm reefs by encouraging excess algal growth. According to Brian Skoloff of The Christian Science Monitor, â€Å"If the reefs vanished, experts say, hunger, poverty and political instability could ensue.Since countless sea life depends on the reefs for shelter and protection from predators, the extinction of the reefs would ul timately create a domino effect that would trickle down to the many human societies that depend on those fish for food and livelihood. There has been a 44% decline over the last 20 years in the Florida Keys, and up to 80% in the Caribbean alone. Coral is very sensitive to changes in seawater. It requires the temperature is moderate but clean without sewage. As long as there is enough time, coral reefs can naturally recover a little natural damage, and sometimes even make the coral reef biological richer.Human activities on coral can cause the pressure of the reef so long and extensive. These pressures may be generated on coral reefs forever. The method of restoring the damage even of coral death is researched into four parts: coral Introduction, what is the coral bleaching phenomenon, causing bleaching, and the strategy to save coral bleaching. Coral bleaching caused by the decline in species diversity of coral reef ecosystems, and even affect the entire marine physical system. Once the coral reef is dying, the whole ecosystem out of balance.There are many actual reasons why the maintenance of biological diversity is important. Many resources can be prepared in the coral reef in order to made pharmaceuticals, chemicals and food. Before the coral reef caused serious destruction, many species will be found disappear. No one knows what we destroy, but if we do not stop destroying the coral reef deterioration. The situation will continue, and will lose a lot of value to be discovered. So we want to make a comprehensive conservation and strategies to save disappearing coral.

Gender Stereotyping in Media Advertisements Essay

The tremendous influence of the media as an important cultural vehicle on the preservation and reinforcement of existing societal norms, beliefs, and behaviors has been under increasing scrutiny from academics, scholars, and feminists in an attempt to understand the code and language within which the media operates and its impacts on various audiences. (Dines, Humez, Hoynes, & Croteau, 2003; Silverstein, Perdue, & Kelly, 1986; Gamble 1997) Lately, there has been a growing concern over the role of the media in helping to maintain the long-standing inequality between sexes in the way that it continues to exploit gender stereotypes overtly as in the case of television programming, to the subliminal messages conveyed by product advertisements, music videos, and other forms of visual entertainment which now include fashion spreads and magazines. (Dines, Humez, Hoynes, & Croteau: 336; Gamble 272) This concern comes amidst allegations that the media, specifically product advertisements, is somehow responsible for the proliferation and reinforcement of unhealthy attitudes and biases against women and women’s bodies, for instance, in warping the definition of physical attractiveness to that of ‘thinness’(Silverstein, Perdue, & Kelly: 519; Gamble 272) and of self-worth to being ‘pretty’ or desired by the male (Dines, Humez, Hoynes, & Croteau: 247). In its many forms, product advertisements, through graphic, in-text, and non-graphic representation, are guilty of exploiting the prevailing societal concepts of femininity and masculinity in their sole objective of increasing demand for the products which translates to increased profit margins. (Wiles, Wiles, & Tjerlund: 35) Product advertisements are also a cause for special concern in that they are easily accessible and are barely constrained by censorship and other legislation. The fact that they are ubiquitous in almost all forms of media—be it print, broadcast, video, and the internet—make them doubly powerful in molding, or warping, the minds of individuals young and old. Dines, Humez, Hoynes, & Croteau (2003) point out, for instance, how â€Å"elements of the pornographic can be located in advertisements,† (p. 336) referring not only to graphic sexual acts or innuendos but to specific representations of female and male constructs and of power relationships between and within these constructs that are seen in advertisements. It is argued that masculinity and femininity are always constructed in the â€Å"conventional† way: that the male is â€Å"bigger, stronger, and has the ability to hurt the women† (Dines, et. al. 336) or in a position of greater power over the women, who are always depicted or associated with the weak, delicate, and passive role. (Gamble 272) In the same manner, women are often portrayed as inferior to men through the use of the following graphic illustrations: â€Å"women appear shorter; men instruct women; women appear to be drifting in deep thought while men? Eyes are focused purposely; and women appear helpless. †(Wiles, Wiles, & Tjerlund, 36) Indeed, one need not look further than the nearest perfume advertisement to see how men and women are portrayed as predator and prey, respectively, signifying the women’s degraded position in the gender stratification. More notable is the apparent absence of ‘others’ in the gender spectrum which may not be totally accepted by societal standards: bisexuals, lesbians, and gays, who barely make it to product advertisements except for those products specifically intended for their market. Furthermore, results of Wiles, Wiles, & Tjerlund’s (1995) study of the portrayal of women in magazines in three countries which include the United States, the Netherlands, and Sweden supported the contention that â€Å"role portrayals presented in magazine advertising depict cultural biases and stereotypes† which tended to portray men in active roles and women as men’s sexual objects or in decorative, passive positions. If art imitates life and culture, this only goes to show the extent to which gender inequality remains as much a challenge to overcome in real, reel, and the simulated world of advertising. Works Cited: Dines, G. , Humez, J. M. M. , Hoynes, D. W. , & D. Croteau. Gender, Race, and Class in Media: A Text Reader. Sage Publications, 2003. Gamble, T. K. & M. W. Gamble, â€Å"Gender and Non-verbal Language. † Contacts: Communicating Interpersonally. Boston, M. A. : Allyn and Bacon, 1997.

Top Research Paper Topics 2013 for College

Top Research Paper Topics 2013 for College Top Research Paper Topics 2013 for College First of all, in order to write a good research paper, you have to understand well what kind of task it is. So, research papers differ from typical essays a little bit. They are longer and require some research work to collect useful information which you can use for your paper. It may sound strange, but the most difficult task for some people is choosing the topic. Actually, its quite normal. If the topic was chosen by your teacher, you have no other choice than to accept it and use it for your research paper. On the other hand, when you have to choose your topic yourself, you can be confused and have trouble choosing the one you really like and interested in. Lets try to do it together. Talking about topics that are relevant in 2013, you can think of everything that happened this year and choose the event that impressed you most. Was it a military conflict in the Middle East? You can analyze the political situation in Syria, Egypt, Afghanistan etc. Also, you may try to find a way out of all the problems in these countries. Maybe the new iPhone 5S is a far more appealing topic for you? Write a paper about modern technology, speaking about how it changed our everyday life, including all the advantages and disadvantages these gadgets have. Are you interested in economy? If yes, you can write about the financial problems in various countries, connecting this factor to financial crisis of 2007-2008. Try to analyze all the opinions on how to cope with such kind of problem and present them in your paper. Actually, there are topics that are relevant, no matter what year it is now. Lets take discrimination. We all seem to be well-educated, polite people without bias against any social group, be it homosexuals, people of different race, religion or gender. However, the problem still remains serious in many countries. Another topic to dwell on is obesity. Is there any way people can eat both delicious and healthy food? Do fast-food restaurants sell junk-food? Is it worth being a vegetarian? In addition, talk about environmental problems and possible ways to make our impact on nature less harmful. There should be some ways to protect rain forests in Brazil, or use alternative power sources (solar or wind energy), use bicycles instead of cars, save electricity and so on. Choosing a topic is just the first step to completing your paper. If you find it too difficult to cope with, or you are pressed for time, you can always rely on our academic writing service for help. We are always ready to lend you a helping hand. At research paper service you have a great opportunity to order a custom written paper online. High quality and plagiarism-free guarantee!

Cincinnati Flood of 1997 essays

Cincinnati Flood of 1997 essays Within two days between March 1 and 3, 1997, a killer storm developed from the Gulf of Mexico from Mississippi all the way to West Virginia and carrying with it a deluge of rain as the worst flood in 33 years (Mazzola 1997). Right on day 1, it was an unusually moist type of weather with a terrifying potential for torrential downpours. It turned violent, bringing thunderstorms and tornadoes across a 250-mile spread of destruction. In five hours, Arkansas experienced 14 tornadoes, which killed at least 24. It lashed nearby states, killing one person a day in Mississippi and Tennessee and its high winds, claiming two lives in Texas. Rains continued on day 2 through Kentucky and Southern Ohio, as swollen streams and creeks poured into the Ohio River (Mazzola). Their levels rose to a foot a day until day 3. Licking River rose to 52 feet, or 12 feet above flood stage. All through day and night 3, 12" rainfall crashed through 40,000 homes and businesses in Louisville. Leaving the place desolate, it drove east to Clermont, Brevin, Adams, Scioto, Lawrence and Gallia counties, before heading for West Virginia, where it eased a bit. By then, 16 West Virginia counties had been declared to be in a state of emergency, as Ohio and Kanawha Rivers filled their banks. Not quite out, it proceeded east-northeast on day 4, but was broken up by a cold front until dissipating in the Great Lakes area. Floods had gone in and out of the Ohio Valley, but past floods could not compare with the wrath of March 1997. The weather freak produced a variety of floods, from flash flooding in hilly terrain and poorly drained areas, to small stream flooding in rural and urban areas. These were followed by very serious flooding along the Ohio River and many of its tributaries (National Oceanic and Atmospheric Administration 1998). It poured into the rivers in northern Kentucky, including the Rolling...