American English Essay Example for Free

American English Essay Ebonics has been an issue in the field of sociolinguistics for quite a long time. It was previously labeled as Negro-standard English, Black English, Black English Vernacular, and African American English Vernacular. It is known to have historical influences from West African and Niger-Congo languages. Researches focused on its similarities and differences with that of the Standard American English to provide explanations to whether it is should be considered as a separate language or at least a dialect of standard American English (Blommeart, 1999). The term Ebonics was coined by Robert Williams in 1973. It referred to the unique variety of language used by African Americans. However, it was not widely used until the proposal of Oakland Schools in 1996. yet, up to this day, experts prefer the term African American to make it consistent with that of other varieties of English like British English, Southern English and among others (http://www. cal. org/topics/dialects/aae. html). One of the differences pointed by Collins (1999) are the phonological processes like consonant cluster simplification and word-final position. For example, words like cold, test, and desk are spelled as col’, tess, and deks in Ebonics. The habitual BE verb of Ebonics may also be confused if will be read as standard English. The debate mainly focused on the issue as whether Ebonics should be a separate language or at least a dialect. It was not a major issue until Ebonics was proposed as a medium for instruction. The sociolinguistic debate was replaced by a more encompassing issue of education, language, culture, and perhaps, politics too. The Ebonics Controversy In December 18, 1996, the Oakland School Board proposed to recognize Ebonics as â€Å"primary language of African American children† and be treated as a subject for Language Art apart from the standard American English (Rickford, 1999). More specifically, the proposal claimed, â€Å"Ebonics was a language that should be recognized, tolerated, and accounted for is instruction of the district’s predominantly African-American student body† (Blommeart, 1999). It would have affected more than 52, 000 students in the district. The aim of this proposed project was improve the educational performance of the urban student body (Blommeart, 1999). The proposal started a debate not just among sociolinguists, but also among educators and politicians. Many of the critics of the proposal argued that the real cause of poor performance of the students was not a question of language but rather the â€Å"lack of effort, motivation, and commitment on the part of the students and their families. † (Blommeart, 1999).

History of and Importance of Handwashing

History of and Importance of Handwashing Introduction Hand washing is the removal of micro-organisms from hands using running water or alcohol rub or gel (Brooker and Waugh, 2007). It is the most effective way of controlling the spread of infectious diseases in hospitals and populated areas. The skin is a vital part of the body that acts as a demarcation between internal and external environment and hence should be kept clean all the time to prevent harmful micro-organisms from entering our bodies (Merchant, 2001). These micro-organisms on the skin can either be resident or transient. Resident micro-organisms also called normal flora are harmless and provide protection against colonization by transient organisms and are not transferred from one person to the other, however they may cause problems if the skin is damaged or if the immune system is weak (Carroll, 2001). Transient micro-organisms are transferred from one person to the other and therefore are capable of spreading infections (Carroll, 2001). Hands can appear as if they are cl ean yet they are contaminated with bacteria, therefore it is always good practice to wash hands regularly. Staff members can pass infectious diseases to patients and patients can also pass diseases to staff members or other patients. Since this is a major issue the author will review hand washing as a means of reducing the spread of infections. The review looks at why hand washing is still an important matter; its historical perspectives, proper hand washing techniques, and the benefits it can bring to patients if practiced properly. The historical background of hand washing explains clearly that most health professionals are found to be the most usual transporters of the bacteria to patients, even though they know that the secret of controlling infections is proper hand hygiene. The production of hand washing liquids dates back from as early as the 19th century when in 1822, Labarraque, a French pharmacist carried out experiments to demonstrate that liquid chloride solutions could successfully eradicate the smell coming from human dead bodies (Safe Care Campaign, 2007). In 1825, Labarraque then recommended the use of these chemicals in hospitals by doctors handling people with contagious diseases in order to moisten their hands but no one followed the instructions (Safe Care Campaign, 2007). In 1846, Dr Ignaz Semmelweis did research on why the ward where medical students were working had a high rate of deaths in comparison to the ward were qualified midwives were working. The results showed that medical students who were having their lectures were rushing to the ward without washing their hands. Instead of washing their hands they were going straight to the patient in the ward. As soon as the error was fixed the death rate started to decline (Advanced Scientific Health, 2010). Recently a report was published by Pfizer limited which showed an increase in MRSA infections. It is believed that 9% of patients in hospitals in England (About 100,000 people per year) have healthcare associated Infections, many of which are due to MRSA. There are between 6,000 and 7,000 MRSA bloods stream Infections each year in patients in NHS hospitals in England. In 2005 in England and Wales, 1,629 deaths Certificates mentioned MRSA as a contributory factor; and MRSA was cited as the main cause of death in 467 of these cases (Pfizer limited, 2009). With this high rate of current MRSA cases in hospitals it is imperative that patients in hospitals, their families and their carers have the correct information avail able to them so that they know the risks of not adhering to proper hand washing techniques when they are in hospitals. Hand washing Technique The NHS is encouraging all health professionals to practice proper techniques of washing hands. It is argued that the more emphasis stressed on this message, the more effective it becomes. The technique of proper hand washing is very essential in any health care setting. The routine or social hand washing technique mainly emphasizes on thorough washing of hands using liquid soap and running water for 15 to 20 seconds without missing any part. It is recommended to use liquid soap delivered from a dispenser as compared to bar soap as the latter may be contaminated by the previous user or the surrounding atmosphere (Carroll, 2001). The diagram in figure 1 in apprentices section below shows most parts of the hands that are frequently missed during hand washing (Nazarko, n.d). These areas that are missed during hand washing may harbor micro-organisms that will then spread to other patients. There is no specific time that is recommended to wash hands. Hands are washed depending on a specif ic task. Health workers are advised to wash their hands when starting or finishing their shift. Several activities such as wound dressing are prone to bringing bacteria to patients and therefore, hand washing should be practiced regularly. Nurses must make sure that they wash their hands before and after they attend another patient and also whenever there is any contact of blood and body fluids or after removal of gloves. It is also advised to wash hands before and after eating and drinking and also after visiting the toilet (Wilson, 2006). Micro-organisms are very tiny such that they cannot be seen with a naked eye. Therefore, it is encouraged to maintain have short nails as longer ones easily accommodate micro-organisms that may be difficult to remove during hand washing. The areas under the watches, rings and bracelets also harbor millions of bacteria; therefore it is also advised not to wear these in hospitals (Gould, 2009). Nurses are also encouraged to wear short- sleeved clot hes. Technological developments have also led to the introduction of next generation ultraviolet light based training kits which are being manufactured by a company called Glowtec. These kits are used to check if the hands have been properly washed before attending to a patient (Glowtec, n.d). This form of hand washing technique is used to see a microscopic dirty surface that cannot be seen by a naked eye therefore improving the control of the infections. Hygienic Hand disinfection is another technique that is used to remove or destroy transient organisms from the skin by washing hands with an antiseptic such as chlorhexidine gluconate, iodine or triclosan for 15-30 seconds and should be carried out before aseptic procedures or during a pandemic situation (Carroll, 2001). The diagram in figure 2 of the appendices section below shows how to wash all areas of the hands to remove any visible contamination of the hands and also to effectively remove transient organisms (Nazarko, n.d) Surgical hand wash is also another technique that is used during surgery which involves the scraping or brushing of the nails with a sterile nail brush, washing hands and forearms with an antiseptic for a minimum of 2 minutes and then drying with a sterile towel (Carroll, 2001). This technique therefore removes transient organisms and reduces the levels of resident organisms. Hand drying is also another vital technique that involves using paper towels, the warm air dryer or sterile towels. This procedure is very important because micro-organisms are spread from one person to the other easily in wet conditions than in dry conditions and drying also reduces the risk of developing sore dry skin (Gould, 2009). Benefits to Patients Patients are the most vulnerable people who are supposed to be taken good care of in a health setting they benefit a lot from hand washing program. It prevents them from cross infection disease among themselves and those who are in care of them (BMJ, 2010). Hand washing is a process that brings hope and assurance to a patient. The patient is likely to recover better. But if a patient is in pain he or she is likely to develop physical or mental problems. If the patient is affected mentally he or she is prone to depression therefore it means the patient would develop infection due to stress environment. Another benefit of hand washing is short stay in hospital, which will enhance the social and economic (no loss of wages) part of a patients life. Eventually this would improve the quality life of a patient. Hand Hygiene Policy (2010) According to Hillingdon Annual Public Health Report 2004 a lot of death can be avoided by hand hygiene, especially those disease caused by MRSA and again a patient is also able to escape isolation in hospitals. Since patients with serious MRSA are sometimes isolated from other patients because of fear of infecting others. Therefore hand washing scheme enhances the well being of a patient. Conclusion Finally the best way of decreasing infectious diseases to patients is hand wash hygiene. According to one of the pioneers of hand wash Dr Semmelweis death rates in hospitals can be lessened if all health professionals follow the idea of handwash. Pathogens and bacteria that are found on hands are said to be the most dangerous causes of infectious diseases unless they are decontaminated by using proper hand technique patients would still suffer the same fate of olden days. According to my opinion hand washing has been discovered long time ago as a main factor of causing infectious diseases but up to now it is still not practiced in a proper way. If each nurse as an individual and those in care underpin the scheme of hand technique in an appropriate manner, they can be a massive change that can bring safety and trust to patients, their families, and friends and even to nurses themselves. Therefore children must be educated on how and when to wash their hands starting from the toddlers so that they can get used to the principle as they grow up. More education training is needed to all health professional on regular basis. If every step of hand washing is followed according to rules and regulations there can be a drastic change in all health care settings.

The History And Uses Of Bioremediation

The History And Uses Of Bioremediation The past decade has shown, in greater or lesser degree, our carelessness and negligence in using our natural resources. The problems associated with contamination of natural resources are prominently increasing in many countries. Contaminated environment generally result from production, use, and disposal of hazardous substances from industrial activities. The problem is worldwide, and the estimated number of contaminated sites is significant. It is now widely recognized that contaminated environment is a potential threat to human health, and its continual discovery over recent years has led to international efforts to remedy many of these sites, to enable the site to be redeveloped for use. To bioremediate, means to use living things to eliminate environmental contamination such as contaminated soil or groundwater. Some microorganisms that live in soil and groundwater naturally eat certain chemicals that are harmful to people and the environment. The microorganisms are able to change these chemicals into water and harmless gases, such as carbon dioxide. Plants can also be used to clean up soil, water or air; this is called phytoremediation Bioremediation is an option that offers the possibility to destroy or render harmless various con ­taminants using natural biological activity. As such, it uses relatively low-cost, low-technology tech ­niques, which generally have a high public acceptance and can often be carried out on site. It will not always be suitable, however, as the range of contaminants on which it is effective is limited, the time scales involved are relatively long, and the residual contaminant levels achievable may not always be appropriate. Although the methodologies employed are not technically complex, considerable experi ­ence and expertise may be required to design and implement a successful bioremediation program, due to the need to thoroughly assess a site for suitability and to optimize conditions to achieve a satisfacto ­ry result. Bioremediation has been used at a number of sites worldwide Here, we intended to assist by providing a straightforward, pragmatic view of the processes involved in bioremediation, the pros and cons of the technique, and the issues to be considered when dealing with a proposal for bioremediation. HISTORY Bioremediation has been described as a treatability technology that uses biological activity to reduce the concentration or toxicity of a pollutant. It commonly uses processes by which microorganisms transform or degrade chemicals in the environment (King 1). This use of microorganisms (mainly bacteria) to destroy or transform hazardous contaminants is not a new idea. Microorganisms have been used since 600 B.C. by the Romans and others to treat their wastewater. Although this same technology is still usedtoday to treat wastewater it has been expanded to treat an array of other contaminants. In fact, bioremediation has been used commercially for almost 30 years. The first commercial use of a bioremediation system was in 1972 to clean up a Sun Oil pipeline spill in Ambler, Pennsylvania CONVENTIONAL STRATEGIES OF REMEDIATION The conventional techniques used for remediation have been to dig up contaminated soil and remove it to a landfill, or to cap and contain the contaminated areas of a site. The methods have some drawbacks. The first method simply moves the contamination elsewhere and may create significant risks in the excavation, handling, and transport of hazardous material. Additionally, it is very difficult and increasingly expensive to find new landfill sites for the final disposal of the material. The cap and contain method is only an temporary solution since the contamination remains on site, requiring monitor ­ing and maintenance of the isolation barriers long into the future, with all the associated costs and potential liability. A better approach than these traditional methods is to completely destroy the pollutants if possi ­ble, or at least to transform them to innocuous substances. Some technologies that have been used are high-temperature incineration and various types of chemical decomposition (e.g., base-catalyzed dechlorination, UV oxidation). They can be very effective at reducing levels of a range of contaminants, but have several drawbacks, principally their technological complexity, the cost for small-scale appli ­cation, and the lack of public acceptance, especially for incineration that may increase the exposure to contaminants for both the workers at the site and nearby residents. Conventional ways of Bioremediation Dig up and remove it to a landfill Risk of excavation, handling and transport of hazardous material Very expensive to find another land to finally dispose these materials Cap and contain the contaminated area. Maintain it in the same land but isolate it Only an temporary solution Requires monitoring and maintenance of isolation barriers for a long time Better approaches: Destroy them completely, if possible Transform them in to harmless substances Drawbacks Technological complexity The cost for small scale application expensive Lack of public acceptance especially in incineration Incineration generates more toxic compounds Materials released from imperfect incineration cause undesirable imbalance in the atmosphere. Ex. Ozone depletion Fall back on earth and pollute some other environment Dioxin production due to burning of plastics leads to cancer May increase the exposure to contaminants, for both workers and nearby residents PRINCIPLES OF BIOREMEDIATION Figure 1: Bioremediation Triangle There are three essential components needed for bioremediation. These three components are microorganisms, food, and nutrients. These three main components shown in Figure 1 are known as the bioremediation triangle. Microorganisms are found almost everywhere on earth with the exception of active volcanoes. So a lack of food and nutrients are usually the missing ingredients that prevent successful bioremediation. Microorganisms find the food they eat in the soil or water where they live. However, if a contaminant is present it can become an additional food source for the microorganisms. The contaminant serves two useful purposes for the microbes. First, the contaminant provides a source of carbon needed for growth. Second,the microbes obtain energy by breaking chemical bonds and transferring electrons away from the contaminant. This is known as an oxidation-reduction reaction. The contaminant that loses electrons is oxidized and the chemical that gains the electrons(electron acceptor) is reduced. The energy gained from the electron transfer is used along with the carbon and some electrons to produce more cells. Microbes generally use oxygenas an electron acceptor but nitrate, sulfate, iron, and CO2 are also commonly used. The use of oxygen as an electron acceptor is called aerobic respiration. The major byproducts of aerobic respiration are carbon dioxide, water, and an increase in the microbe population. Anaerobic respiration uses nitrate, sulfate, iron, or CO2 as the electron acceptor instead of oxygen. Anaerobic respiration can occur after the oxygen has been depleted by aerobic respiration or where there is not sufficient oxygen in the first place. The process of anaerobic degradation has been ignored for many years. However, recently it has been gaining more attention; There are also several nutrients that must be accessible to the microorganisms for bioremediation to be successful. These include moisture, nitrogen, phosphorus, and other trace elements. Microorganisms like other organisms need moisture to survive and grow.In addition, microbes depend on the moisture to transport food to them since they do not have mouths. The optimal moisture content for microbes in the vadose zone has been determined to be between 10 and 25% (King 16). Besides moisture, nitrogen (ammonia)and phosphorus (orthophosphate) are two major nutrients needed for the microorganisms. The microorganisms also require minor elements such as sulfur, potassium, magnesium,calcium, manganese, iron, cobalt, copper, nickel, and zinc (King 19). However, these minor elements are usually available in the environment in sufficient amounts where nitrogen and phosphorus may be lacking and need to be added. There are many contaminants susceptible to bioremediation. Petroleum hydrocarbons, i n particular, benzene, toluene, ethylbenzene, and xylene (BTEX), the major components of gasoline, have been biodegraded using this technology. In addition, alcohols, ketones, and esters are well established as being biodegradable by microorganisms. Many other contaminants are emerging as treatable using bioremediation such as halogenated aliphatics, halogenated aromatics, polychlorinated biphenyls, and nitroaromatics. FACTORS AFFECTING BIOREMEDIATION The factors affecting bioremediation can be divided into following categories. Microbial factors Environmental factors Microbial Factors Microorganisms can be isolated from almost any environmental conditions. Microbes will adapt and grow at subzero temperatures, as well as extreme heat, desert conditions, in water, with an excess of oxygen, and in anaerobic conditions, with the presence of hazardous compounds or on any waste stream. The main requirements are an energy source and a carbon source. Because of the adaptability of microbes and other biological systems, these can be used to degrade or remediate environmental hazards. We can subdivide these microorganisms into the following groups Aerobic Anaerobic Ligninolytic Fungi Methylotrophs Aerobic These microbes have often been reported to degrade pesticides and hydrocarbons, both alkanes and polyaromatic compounds. Many of these bacteria use the contaminant as the sole source of carbon and energy. Examples of aerobic bacteria recognized for their degradative abilities are Pseudomonas, Alcaligenes, Sphingomonas, Rhodococcus, and Mycobacterium. Anaerobic Anaerobic bacteria are not as frequently used as aerobic bacteria. There is an increasing interest in anaerobic bacteria used for bioremediation of polychlorinated biphenyls (PCBs) in river sediments, dechlorination of the solvent trichloroethylene (TCE), and chloroform. Ligninolytic fungi Fungi such as the white rot fungus Phanaerochaete chrysosporium have the ability to degrade an extremely diverse range of persistent or toxic environmental pollutants. Common substrates used include straw, saw dust, or corn cobs. Methylotrophs Aerobic bacteria that grow utilizing methane for carbon and energy. The initial enzyme in the pathway for aerobic degradation, methane monooxygenase, has a broad substrate range and is active against a wide range of compounds, including the chlorinated aliphatics trichloroethylene and 1,2-dichloroethane. For degradation it is necessary that bacteria and the contaminants be in contact. This is not easily achieved, as neither the microbes nor contaminants are uniformly spread in the soil. Some bacteria are mobile and exhibit a chemotactic response, sensing the contaminant and moving toward it. Other microbes such as fungi grow in a filamentous form toward the contaminant. It is possible to enhance the mobilization of the contaminant utilizing some surfactants such as sodium dodecyl sulphate (SDS) Microbes are used to degrade gasoline, the most common contaminant of groundwater in the United States. Adding powdered seaweed to DDT-contaminated soil boosts the cleaning activity of DDT-eating microbes. In one test site, 80% of the DDT was removed after six weeks. Microbes and fungi are used in air filters to control odours from sewage treatment plants and in the paint industry. A gene for a protein found in rat livers that binds with toxic metals has been inserted in both tobacco plants and algae. With this gene, the tobacco plant and the algae are able to extract several hundred times more toxic metal compounds from soil or water compared to plants without the gene. One particular microbe degrades polycyclic aromatic hydrocarbons (PAHs), which are cancer-causing petroleum by-products. The microbes, called simply sulfate-reducers, are able to attack PAHs in the sediment of Boston Harbor where scientists thought the contaminant could not be treated due to lack of oxygen. Examples of microbes used for bioremediation include: Deinococcus radiodurans bacteria have been genetically modified to digest solvents and heavy metals, as well as toluene and ionic mercury from highly radioactive nuclear waste. Geobacter sufurreducens bacteria can turn uranium dissolved in groundwater into a non-soluble, collectable form. Dehalococcoides ethenogenes bacteria are being used in ten states to clean up chlorinated solvents that have been linked to cancer. The bacteria are naturally found in both soil and water and are able to digest the solvents much faster than using traditional clean-up methods. Thermus brockianus, found in Yellowstone National Park, produces an enzyme that breaks down hydrogen peroxide 80,000 times faster than current chemicals in use. Alcaligenes eutrophus, naturally degrades 2,4-D, the third most widely used herbicide in the U.S. Some contaminants potentially suitable for bioremediation. Class of contaminants Specific examples Aerobic Anaerobic Potential sources Chlorinated solvents Trichloroethylene + Drycleaners Perchloroethylene Chemical manufacture Polychlorinated biphenyls 4-Chlorobiphenyl + Electrical manufacturing 4,4 Dichlorobiphenyl Power station Railway yards Chlorinated phenol Pentachlorophenol + Timber treatment Landfills BTEX Benzene + + Oil production and storage Toluene Gas work sites Ethylbenzene Airports Xylene Paint manufacture Port facilities Railway yards Chemical manufacture Polyaromatic hydrocarbons Naphthalene + Oil production and storage (PAHs) Antracene Gas work sites Fluorene Coke plants Pyrene Engine works Benzo(a)pyrene Landfills Tar production and storage Boiler ash dump sites Power stations Pesticides Atrazine + + Agriculture Carbaryl Timber treatment Carbofuran Pesticide manufacture Coumphos Recreational areas ENVIRONMENTAL FACTORS 1. Nutrients Although the microorganisms are present in contaminated soil, they cannot necessarily be there in the numbers required for bioremediation of the site. Their growth and activity must be stimulated. Biostimulation usually involves the addition of nutrients and oxygen to help indigenous microorgan ­isms. These nutrients are the basic building blocks of life and allow microbes to create the necessary enzymes to break down the contaminants. All of them will need nitrogen, phosphorous, and carbon (e.g., see Table below). Carbon is the most basic element of living forms and is needed in greater quantities than other elements. In addition to hydrogen, oxygen, and nitrogen it constitutes about 95% of the weight of cells.Phosphorous and sulphur contribute with 70% of the remainders. The nutritional requirement of carbon to nitrogen ratio is 10:1, and carbon to phosphorous is 30:1. 3. Environmental requirements Optimum environmental conditions for the degradation of contaminants are reported in Table below: Parameters Condition required for microbial activity Optimum value for an oil degradation Soil moisture 25-28% of water holding capacity 30-90% Soil pH 5.5-8.8 6.5-8.0 Oxygen content Aerobic, minimum air-filled pore space of 10% 10-40% Nutrient content N and p for microbial growth C:N:P = 100:10:1 Temperature ( °C) 15-45 20-30 Contaminants Not too toxic Hydrocarbon 5-10% of dry weight of soil Heavy metals Total content 2000 ppm 700 ppm Type of soil Low clay or silt content 4. Environmental conditions affecting degradation Microbial growth and activity are readily affected by pH, temperature, and moisture. Although microorganisms have been also isolated in extreme conditions, most of them grow optimally over a nar ­row range, so that it is important to achieve optimal conditions. If the soil has too much acid it is possible to rinse the pH by adding lime. Temperature affects bio ­chemical reactions rates, and the rates of many of them double for each 10  °C rise in temperature. Above a certain temperature, however, the cells die. Plastic covering can be used to enhance solar warming in late spring, summer, and autumn. Available water is essential for all the living organisms, and irrigation is needed to achieve the optimal moisture level. The amount of available oxygen will determine whether the system is aerobic or anaerobic. Hydrocarbons are readily degraded under aerobic conditions, whereas chlorurate compounds are degraded only in anaerobic ones. To increase the oxygen amount in the soil it is possible to till or sparge air. In some cases, hydrogen peroxide or magnesium peroxide can be introduced in the environment. Soil structure controls the effective delivery of air, water, and nutrients. To improve soil structure, materials such as gypsum or organ ic matter can be applied. Low soil permeability can impede move ­ment of water, nutrients, and oxygen; hence, soils with low permeability may not be appropriate for in situ clean-up techniques. STRATEGIES AND TECHNIQUES INVOLVED IN BIOREMEDIATION Basically two types of techniques are involved in Bioremediation In situ Bioremediation (at the site) Ex situ Bioremediation (away from the site) In situ Bioremediation In situ techniques are defined as those that are applied to soil and groundwater at the site with minimal disturbance. These techniques are generally the most desirable options due to lower cost and fewer disturbances since they provide the treatment in place avoiding excavation and transport of contaminants. In situ treatment is limited by the depth of the soil that can be effectively treated. In many soils effective oxygen diffusion for desirable rates of bioremediation extend to a range of only a few centimetres to about 30 cm into the soil, although depths of 60 cm and greater have been effectively treated in some cases. In situ Bioremediation types: Bioventing is the most common in situ treatment and involves supplying air and nutrients through wells to contaminated soil to stimulate the indigenous bacteria. Bioventing employs low air flow rates and provides only the amount of oxygen necessary for the biodegradation while minimizing volatiliza ­tion and release of contaminants to the atmosphere. It works for simple hydrocarbons and can be used where the contamination is deep under the surface. In situ biodegradation involves supplying oxygen and nutrients by circulating aqueous solutions through contaminated soils to stimulate naturally occurring bacteria to degrade organic contaminants. It can be used for soil and groundwater. Generally, this technique includes conditions such as the infil ­tration of water-containing nutrients and oxygen or other electron acceptors for groundwater treatment. Biosparging involves the injection of air under pressure below the water table to increase groundwater oxygen concentrations and enhance the rate of biological degradation of contam ­inants by naturally occurring bacteria. Biosparging increases the mixing in the saturated zone and there ­by increases the contact between soil and groundwater. The ease and low cost of installing small-diam ­eter air injection points allows considerable flexibility in the design and construction of the system Bioaugmentation. Bioremediation frequently involves the addition of microorganisms indigenous or exogenous to the contaminated sites. Two factors limit the use of added microbial cultures in a land treatment unit: 1) nonindigenous cultures rarely compete well enough with an indigenous population to develop and sustain useful population levels and 2) most soils with long-term exposure to biodegrad ­able waste have indigenous microorganisms that are effective degrades if the land treatment unit is well managed. Ex situ bioremediation Ex situ techniques are those that are applied to soil and groundwater at the site which has been removed from the site via excavation (soil) or pumping (water). These techniques involve the excavation or removal of contaminated soil from ground. Ex situ Bioremediation types: These techniques involve the excavation or removal of contaminated soil from ground. Landfarming is a simple technique in which contaminated soil is excavated and spread over a pre ­pared bed and periodically tilled until pollutants are degraded. The goal is to stimulate indigenous biodegradative microorganisms and facilitate their aerobic degradation of contaminants. In general, the practice is limited to the treatment of superficial 10-35 cm of soil. Since landfarming has the potential to reduce monitoring and maintenance costs, as well as clean-up liabilities, it has received much atten ­tion as a disposal alternative. Composting is a technique that involves combining contaminated soil with nonhazardous organ ­ic amendants such as manure or agricultural wastes. The presence of these organic materials supports the development of a rich microbial population and elevated temperature characteristic of composting. Biopiles are a hybrid of landfarming and composting. Essentially, engineered cells are con ­structed as aerated composted piles. Typically used for treatment of surface contamination with petro ­leum hydrocarbons they are a refined version of landfarming that tend to control physical losses of the contaminants by leaching and volatilization. Biopiles provide a favorable environment for indigenous aerobic and anaerobic microorganisms. Bioreactors Slurry reactors or aqueous reactors are used for ex situ treatment of contaminated soil and water pumped up from a contaminated plume. Bioremediation in reactors involves the pro ­cessing of contaminated solid material (soil, sediment, sludge) or water through an engineered con ­tainment system. A slurry bioreactor may be defined as a containment vessel and apparatus used to cre ­ate a three-phase (solid, liquid, and gas) mixing condition to increase the bioremediation rate of soil-bound and water-soluble pollutants as a water slurry of the contaminated soil and biomass (usually indigenous microorganisms) capable of degrading target contaminants. In general, the rate and extent of biodegradation are greater in a bioreactor system than in situ or in solid-phase systems because the contained environment is more manageable and hence more controllable and predictable. Despite the advantages of reactor systems, there are some disadvantages. The contaminated soil requires pre-treatment (e.g., excavation) or alternatively the contaminant can be stripped from the soil via soil washing or physical extraction (e.g., vacuum extraction) before being placed in a bioreactor. Monitoring bioremediation The process of bioremediation can be monitored indirectly by measuring the Oxidation Reduction Potential or redox in soil and groundwater, together with pH, temperature, oxygen content, electron acceptor/donor concentrations, and concentration of breakdown products (e.g. carbon dioxide). This table shows the (decreasing) biological breakdown rate as function of the redox potential. Process Reaction Redox potential (Eh in mV) Aerobic: O2 + 4eà ¢Ã‹â€ Ã¢â‚¬â„¢ + 4H+ à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ 2H2O 600 ~ 400 Anaerobic: Denitrification 2NO3à ¢Ã‹â€ Ã¢â‚¬â„¢ + 10eà ¢Ã‹â€ Ã¢â‚¬â„¢ + 12H+ à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ N2 + 6H2O 500 ~ 200 Manganese IV reduction MnO2 + 2eà ¢Ã‹â€ Ã¢â‚¬â„¢ + 4H+ à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ Mn2+ + 2H2O 400 ~ 200 Iron III reduction Fe(OH)3 + eà ¢Ã‹â€ Ã¢â‚¬â„¢ + 3H+ à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ Fe2+ + 3H2O 300 ~ 100 Sulfate reduction SO42à ¢Ã‹â€ Ã¢â‚¬â„¢ + 8eà ¢Ã‹â€ Ã¢â‚¬â„¢ +10 H+ à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ H2S + 4H2O 0 ~ à ¢Ã‹â€ Ã¢â‚¬â„¢150 Fermentation 2CH2O à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ CO2 + CH4 à ¢Ã‹â€ Ã¢â‚¬â„¢150 ~ à ¢Ã‹â€ Ã¢â‚¬â„¢220 Types of Bioremediation Bioremediation techniques can be subdivided into various based on following factors Based on type of atmosphere in which Bioremediation takes place it can be divided into two types Engineered Bioremediation Intrinsic Bioremediation Based on Type of organism being used for Bioremediation Mycoremediation Phytoremediation ENGINEERED BIOREMEDIATION Factors effecting engineered bioremediation Contact between the microbes and the substrate Proper physical environment Nutrients Oxygen Absence of toxic compounds Sources of microorganisms From contaminated field sites(with varying environmental conditions subzero temperatures or extreme heat, desert conditions or in water, with excess of oxygen or in anaerobic conditions, with presence of hazardous compounds or on any waste stream) From culture collections Genetically Engineered Microorganisms (GEMs) Electro kinetically enhanced bioremediation (EEB) is a method of engineered bioremediation of soil contaminated by such organic compounds as solvents and petroleum products. As depicted schematically in the figure, EEB involves the utilization of controlled flows of liquids and gases into and out of the ground via wells, in conjunction with electrokinetic transport of matter through pores in the soil, to provide reagents and nutrients that enhance the natural degradation of contaminants by indigenous and/or introduced microorganisms. The operational parameters of an EEB setup can be tailored to obtain the desired flows of reagents and nutrients in variably textured and layered soils of variable hydraulic permeability and of moisture content that can range from saturation down to as little as about 7 percent. A major attractive feature of EEB is the ability to control the movements of charged anionic and cationic as well as noncharged chemical species. The basic components of electrokinetic enhancement of bioremediation are the following: * Ions are transported by electromigration; that is, with minimum transport of liquid through the soil. The ions of interest include nutrient agents, electron donors (e.g., lactate) or electron acceptors (e.g., nitrate or sulfate) added to the soil. Electromigration is utilized as an efficient mode of electrokinetic transport in vadosezone soils. * Water in soil is pumped (horizontally or vertically, depending on the positions of electrode wells) by induced electro-osmotic flow. Whereas the hydraulic flow used in older methods decreases with decreasing pore size and is thus not effective for treating tightly packed soil, electro-osmotic flow is less restricted by tight packing. Electro-osmosis is utilized to enhance the transport of both ions and such noncharged particles as micro-organisms, by moving water from anodes (positive electrodes) toward cathodes (negative electrodes). * Electrophoresis induced in soil under an applied electric field is used to control the transport and/or distribution of micro-organisms throughout the treated soil volume. The beneficial effect of electrophoresis can be augmented or otherwise modified by use of electro-osmotic flushing of the soil. * The applied electric current can be utilized to heat the soil to the optimum temperature for bioremediation. * The gaseous and liquid products of electrolysis of water in the soil are removed from electrode wells and mixed and reinjected into the ground as needed to maintain the pH of the soil within a range favorable for bioremediation. Disadvantages Mostly GEMs do not work the way we expect: Lab strains become food source for soil protozoa Inability of GEMs to contact the compounds to be degraded Failure of GEMs to survive/compete indigenous microorganisms. Mostly due to lack / decreased activity of House Keeping Genes. INTRINSIC BIOREMEDIATION It is a natural attenuation process that leads to the decrease in contaminant levels in a particular environment due to unmanaged physical, chemical and biological processes. Conversion of environmental pollutants into the harmless forms through the innate capabilities of naturally occurring microbial population is called intrinsic bioremediation. However, there is increasing interest on intrinsic bioremediation for control of all or some of the contamination at waste sites. The intrinsic i.e. inherent capacity of microorganism, to metabolize the contaminants should be tested at laboratory and field levels before use for intrinsic bioremediation. Through site monitoring programmes progress of intrinsic bioremediation should be recorded time to time. The conditions of site that favours intrinsic bioremediation are ground water flow throughout the year, carbonate minerals to buffer acidity produced during biodegradation supply of electron acceptors and nutrients for microbial growth and absence of toxic compounds. The other environmental factors such as pH concentration, temperature and nutrient availability determine whether or not biotransformation takes place. Bioremediation of waste mixtures containing metals such as Hg, Pb, As and cyanide at toxic concentration can create problem (Madsen, l99l). The ability of surface bacteria to degrade a given mixture of pollutants in ground water is dependent on the type and concentration of compounds, electron acceptor and duration of bacteria exposed to contaminants. Therefore, ability of indigenous bacteria degrading contaminants can be determined in laboratory by plate count and macrocosm studies Example: Microbes in Hudson River mud developed an ability to partially degrade PCB (Poly Chlorinated Biphenyls) Process occurs in two steps Partial dehalogenation of PCBs occurs naturally under anaerobic conditions Less chlorinated residues Then mud is aerated to promote the complete degradation of these less chlorinated residues MYCOREMEDIATION Mycoremediation is a form of bioremediation, the process of using fungi to return an environment (usually soil) contaminated by pollutants to a less contaminated state. The term Mycoremediation was coined by Paul Stam

Hatred in Notes of a Native Son Essay -- James Baldwin

The Destructive Nature of Hatred Hatred for white society was a common sentiment among the black community during the 1950s. These feelings were expressed through different mediums, ranging from music and art, to the written word. But James Baldwin, a popular black writer during this time period, does not harp on this subject. Instead of preaching about his hatred for white America, Baldwin utilizes his narrative and analysis techniques to illustrate the destructive nature of the black society’s hatred for white society in â€Å"Notes of a Native Son†. The hatred many African Americans possessed during the 1950s caused multiple riots. Baldwin touches on this in â€Å"Notes of a Native Son†, by mentioning the Harlem riots that broke out during the time of his father’s death. Baldwin states that â€Å"it would have been better to have left the plate glass as it had been and the goods lying in the stores† (Baldwin 82), but â€Å"it would have also been intolerable, for Harlem had needed something to smash† (82). The black community, infuriated by improper police action, exploded into a fury of anger. While Baldwin does not argue against the riots, he points out their futility. The riots, as Baldwin points out, did not cross the ghetto lines. Instead of wreaking havoc in white neighborhoods, the black mob simply destroyed its own area. The mob had succumbed to its hatred for white society, but in doing so, destroyed its own neighborhood. Thus, Baldwin points out the self-destructive nature of the black community’s hatred. Instead of causing damage to white society, or even white property, the black community ended up inflicting wounds on its own people. Baldwin does not stop with this event to illustrate the irony of the black commun... ... and from it learns two key lessons to prevent a similar destruction of his own life. Baldwin first states that one must accept that â€Å"injustice is commonplace† (84). Prejudice, according to Baldwin, will always exist in life, whether it is against race, color or creed. But while prejudice is ever-present, Baldwin concludes â€Å"one must never†¦accept these injustices as commonplace but must fight them with all one’s strength† (84). In order to succeed in this fight, one must keep his â€Å"own heart free of hatred† (84). Thus according to Baldwin, the real fight is not black society versus white society, but rather man versus himself. It is only by winning this battle that one can avoid the path of destruction. Works Cited Baldwin, James. â€Å"Notes of a Native Son.† 1955. James Baldwin: Collected Essays. Ed. Toni Morrison. New York: Library of America, 1998. 63-84.

Free Grapes of Wrath Essays: Steinbecks Portrait of Fear :: Grapes Wrath essays

Portrait of Fear in The Grapes of Wrath Steinbeck shows throughout The Grapes of Wrath that mankind is afraid of failure. Although that fear is present in both the desperate migrant workers and the big, ruthless land owners, Steinbeck uses Al Joad's character to his full advantage t model this characteristic of man. Al's personal fear of failure motivates him to do well in life in comparison to his male role models, as well as to help support the family. This is conveyed through Al's sense of responsibility to his family, his careful nature, and his moody and defensive behavior. Al's sense of responsibility to his family is a major element in his determination not to fail. His knowledge and operation of automobiles are Al's major contribution to the family: "He might be a musking goat sometimes, but this was his responsibility, this truck, its running, and its maintenance...And everyone respected him and his responsibility" (Steinbeck, pages 131 and 132). Al not only helps the family succeed in getting to California by taking on this responsibility, he also makes up for other areas of his character in which he feels he is failing or lacking. Such an area of character might be his apathy towards letting his family know his whereabouts when he disappears for days at a time in Oklahoma. Al's careful nature is another obvious sign that he does not want to fail. He feels that precaution is the only way to prevent something from going wrong and ultimately failing. This is visible in his meticulous care of the truck: "Al grew tense over the wheel. A little rattle had developed in the engine. He speeded up and the rattle increased...Al blew his horn and pulled the car to the side of the road" (page 225). Al's care, though obvious only in that of the truck, definitely suggests that should he fail to properly maintain the truck, he would fail himself and his family as well. To offset such an event, Al constantly watches for and prevents any possible problems with the truck. Al's moody and defensive behavior is also a strong example of his resolution not to fail. Although his attitude could be attributed to adolescent arrogance, one who examines Al's character can see that he has more pressure placed upon him than most of the other members of the family.

Diels alder reaction Essay

Result: For the Diels-Alder reaction: Maleic acid is 0.002 mol 2,3-dimethyl-1,3-butadiene is 0.002 mol The theoretical yield is 0.36g Cycloaddition product is 0.358g (maybe it was not completely dry when I weighted.) The % yield of Diels-Alder reaction is 99.4% For the hydrolysis: The theoretical yield of hydrolysis is 0.396g The experimental product yield is 0.28g (some solid left on the filter paper and some for the melting point measurement.) The % yield of hydrolysis is 70.7% The cycloaddition of a conjugated diene and a dienophile, which is drove by forming new ÏÆ'-bonds from Ï€-electrons of the diene and dienophile, which are energetically more stable than the Ï€-bonds. During the Diels-Alder reaction, the temperature should be kept between 60-70 â„Æ'. Because the boiling point of the butadiene is low and do not let it vaporize. After cycloaddition, pour the reaction mixture into 50 ml water under room temperature, the product would precipitate because of the low temperature. The acid added for the hydrolysis part is very important because acids have been used to accelerate the rate of the intra-molecular Diels-Alder reaction. The PEG 200 used in this experiment as the solvent for maleic anhydride is  make the experiments more green, which is less harmful and more environmental friendly. The melting point measurement is helping us to determine what we get basically. Compare with the IR spectra I got, the peak at 1792.62 cm-1 in the first spectra express the C=O bonds of the initial cycloaddition product, and the peak at 1697.14 cm-1 in the second IR spectra shows the C=O bonds of carboxylic acid ( RCOOH) of the final product.

Nathaniel Hawthorne’s as Anti-Transcendentalist Essay

Nathaniel Hawthorne an American romantic writer, whose literature is known for its Anti-Transcendentalism, wrote Young Goodman Brown and The Scarlet Letter. Nathaniel Hawthorne is a writer during the American Romantics, where the majority of writing is focused on nature, supernatural elements; one’s psychology and the criticism of society’s â€Å"norm†. Nathaniel is Hawthorne known for his notorious Anti-Transcendentalist literature. Anti-Transcendentalism ideals are about one’s evil and inner and sinful nature, where everyone is born evil and no matter what, and that humanity is evil and destructive. Hawthorne is not able to accept the optimism of the Transcendentalists and through his writing he tries to look for truths in one’s heart and mind. Hawthorne’s use of symbols, characters, and themes in his literature classify his writings as Anti-Transcendentalist.Through the use of character development Hawthorne’s literature can be clas sified as Anti-Transcendentalist. In both pieces of literature Hawthorne uses characters who act as the epitome of Anti-Transcendentalism. The Scarlet Letter has two imperative characters that exemplify Anti-Transcendentalist. First we have Dimmesdale; he is a minister in the town and is one of the most highly respected men in Boston. In reality Dimmesdale is a sinner and an adulterer as he slept with Hester, another man’s wife and got her pregnant. Hester’s punishment for her actions are; public humiliation, and the Scarlet Letter. Though Dimmesdale is not revealed as her accomplice over time he himself grows a Scarlet Letter of his own. â€Å"Most of the spectators testified to having seen, on the breast of the unhappy minister, a Scarlet Letter†¦Mr. Dimmesdale, on the very day when Hester Prynne first wore her ignominious badge, had begun a course of penance†(SL 211). When Hawthorne reveals Dimmesdale having a Scarlet Letter it expresses the ideals of Anti-Transcendentalism where his own Scarlet Letter is the example of one’s inner darkness and evil that is inside of him. In Young Goodman Brown after Goodman Brown witnesses all of the townspeople participating in a witchcraft ceremony and comes back to his home he sees the world in a new perspective. â€Å"The next morning Goodman Brown came slowly into the streets of Salem staring around him like a bewildered man†(YGB 7). He is never the same and trusts no one, including his wife. It says that he snatched away the children that Goody Cloyse was talking to and when his wife embraced him he just walked away.(YGB 7 )Hawthorne uses Goodman Brown to show that everyone is evil inside and that he human spirit is destructive. Character development acknowledges a role in how Hawthorne’s literature should be classified as Anti-Transcendentalist.Character Development is not the only factor that classifies Hawthorne’s literature as Anti-Transcendentalist; symbols take on an enormous role as well. In the Scarlet Letter two symbols are Pearl, and the actual Scarlet Letter. Pearl is not only a peculiar child for her age she has a much deeper meaning. Pearl is Hester’s living example of her sin. Pearl’s purpose in the Scarlet Letter is to represent sin, but not only to Hester but in the world as well. The Actual Scarlet Letter is also a symbol which represents not only sin, but the Anti-Transcendentalist idea that your sins will never go away, sin will remain evident inside you and around you. These two examples could not exemplify Anti-Transcendentalist beliefs any more as its primary focus is about sinfulness and how people view sin. In Young Goodman Brown a few symbols that embody Anti-Transcendentalism are the forest and the old man who is meant to be the devil. The forest in both of Hawthorne’s literature has a dark meaning towards it and also is a place where no good can happen Goodman Brown believes that the devil could be present in the forest, and when he sees a woman from his town he hides as he is ashamed to be walking in the forest. The forest is characterized as devilish, frightening, and dark. The old man is also a symbol which is portrayed as the devil. He is used to represent the destructiveness of the human spirit and to show the evil within humanity. All of these characteristics contribute to classify Hawthorne’s writing as Anti-Transcendentalist. Aside from characters and symbols Hawthorne uses themes in his literature which contribute to classifying his writings as Anti-Transcendentalist. The most prominent theme in both pieces of his literature is the, nature of evil in humanity. The Scarlet Letter uses the â€Å"Black Man† as an alter ego to Chillingworth who is a representation for the Devil. On the outside Chillingworth is a doctor who is supposed to help people when they are sick but inside he is evil. Instead of giving Dimmesdale life he is making him sick, as he is taking life and making it miserable. â€Å"‘Come away, or yonder old black man will catch you! He hath got hold of the minister already. Come away, mother or he will catch you!’†(SL 61) The quote is from Pearl who understands Chillingworth is the devil and has already captured and made Dimmesdale’s life horrible. Another instance of the evil in humanity partakes in the Story of Young Goodman Brown where it contains a greate r depth of evil in humanity. The Scarlet Letter is only one man consumed by the devil but in Young Goodman Brown the whole town appears to be taking part in a witchcraft ceremony. When he is taken into the forest he sees the minister, a deacon and many more respected men of his town are evil. â€Å"He recognized a score of church members of Salem†¦Good old Deacon Gookin had arrived, his reserved pastor†(YGB 6) These men and women who are highly respected are taking part in English witchcraft. Hawthorne is expressing that humans are capable of inner darkness and evil, which enable his literature to be classified as Anti-Transcendentalist. Symbols, characters, and themes are the elements that Hawthorne uses to show how his literature can be classified as Anti-Transcendentalist. The symbols in both pieces of Hawthorne’s literature represent sin, and evil, both which are qualities of Anti-Transcendentalism. All the characters in Hawthorne’s literature contain evidence of sinful nature, inner darkness and the destructiveness of the human spirit. These qualities are most prominent in Chillingworth and Dimmesdale and especially with Goodman Brown. Lastly Hawthorne’s primary theme in all his literature is the nature of evil in humanity. Chillingworth exemplifies this theme greatly as well as the towns’ people in Young Goodman Brown. The way Hawthorne writes and his use of symbols, themes, and characters classify his writing as Anti-Transcendentalist.