Gender Differences in Neurotoxicity

Gender Differences in Neurotoxicity Abstract Neurotoxicity is damage to the structure and/or function of the peripheral and central nervous systems. It is a common outcome of exposure to hundreds of environmental chemicals, which act via a wide range of mechanisms. Due to the fundamental importance of the nervous system to a fully functioning body, the neurotoxic effects of many chemicals have been well investigated. There is evidence from a number of studies of a difference in susceptibility to environmental neurotoxins between genders. Males appear to be more vulnerable than females. There may be many reasons for this difference, a key one being the neuroprotective activities of the gonadal (sex) hormones, which differ between males and females. The female hormone, oestrogen, is thought to have greater protective activity, from a wide range of chemicals than the male hormone, testosterone. This report will examine the available evidence of a gender difference in susceptibility to environmental neurotoxins, and look into the actions of hormones within the nervous system as one of the main reasons for this difference. Introduction The nervous system (NS) is a fundamental component of a fully functioning human body. Due to the immense importance of the NS, any damage that occurs to this system will have huge repercussions throughout the whole body. Unfortunately, the NS is extremely vulnerable, and neurons, with their unique shape, and long, thin extensions protruding from their cell bodies, are highly susceptible to degeneration, from ageing and from exogenous substances (1, 2). It has been observed that exposure to a range of different environmental chemicals can have adverse effects on the NS, resulting in degeneration of neurons, and leading to onset of various neurological diseases (2, 3). The developing NS in particular is extremely sensitive to the effects of such chemicals (2, 4). Prenatal, and early postnatal, exposure to environmental chemicals, such as lead and those in tobacco smoke, can affect the developmental process within the Central Nervous System (CNS). This can lead to slowed and incorrect development, and neurological problems in the early years of life (4). From both animal studies, and human case reports of inadvertent exposures, there is also evidence to suggest a difference between males and females in their susceptibilities to neurotoxicity of some environmental chemicals (5). There are a number of reasons why this may be, including differences in amounts and activities of metabolic enzymes, differences in rates of absorption between the sexes, different rates of clearance of exogenous substances from the body, and differences in exposure to neurotoxic chemicals; diet, hobbies, occupations, etc (6). However, a key reason may be the neuroprotection that is conferred by gonadal hormones, and their metabolites, within the NS (5). The aim of this report is to research evidence of sex differences in responses to environmental chemicals, and investigate hormonal influences as one of the reasons for this difference. Neurotoxicity of Environmental Chemicals Neurotoxicity is a term used to describe damage to the structure and/or function of the peripheral NS (PNS) and CNS, brought about by exposure to particular exogenous substances (7, 8), which act via a range of mechanisms to induce cellular changes, and often cell death (7). Neurotoxicity can be seen in all ages of individuals exposed to hazardous chemicals, however, the developing NS is particularly vulnerable to their effects (2, 4, 7). Development of the NS involves a series of very specific steps, over a prolonged time period, each one occurring only when the previous is finished, and disruption to these events leads to incorrect development and neurological problems (4). The blood-brain barrier (BBB), which prevents many substances from passing to the brain, is not fully complete until several months of age, leaving the NS susceptible to damage (7). The entire NS is not fully mature until puberty (4). A great number of the reports published concerning neurotoxic effects of chemi cals have reported observations on child subjects. This is due to the fact that the developing NS is much more vulnerable, and so the neurotoxic effects may be more easily noticed. There are over 200 chemicals that have been confirmed as neurotoxic to humans (and other animals)as a result of exposure to them (3). A number of these chemicals are identified in Panel 1 (3), and can be divided into groups; metals, organic solvents, pesticides, and other neurotoxic chemicals. Panel 1. There are over 200 chemicals known to cause neurotoxicity in humans. This list identifies some common ones. Adapted from (3). Chemicals in bold and red are those identified within this report. Different toxins have distinct mechanisms through which they influence the NS. This depends on dose, route and duration of exposure (9). Those chemicals which are most widespread in the environment, and those which cause the most drastic effects, have been extensively investigated, and many of the mechanisms causing neurotoxicity have been identified (9). Given the knowledge of these effects, it is important to investigate the possible neurotoxic influences of the large number of other chemicals prevalent in the environment. Mechanisms of neurotoxicity The main mechanisms encompassed by the afore-mentioned groups of substances include; induction of oxidative stress, alterations to neurotransmitter synthesis including inhibition of synaptic signalling, accumulation of the substance within mitochondria leading to dysfunction, alterations to the flow of ions across neuronal membranes, activation of second messengers to induce apoptosis or inhibit neurogenesis, disruption of DNA/RNA, affecting the differentiation and functioning of glial cells, to indirectly influence neuronal cells, alterations to membrane fluidity, abnormal expression of neurotrophic factors (7, 10-20). There is a requirement for metals in many body processes, including within the NS, providing an additional mechanism by which exogenous metals can induce neurotoxicity (17). They can compete with essential metals for protein binding sites and influence cellular processes (17). For example, lead competes with zinc, which is known to have binding sites present in many important receptor channels, such as the N-methyl-D-aspartate (NMDA) receptor involved in glutamate signalling at the synapse. Lead can displace zinc, and therefore alter functioning of these channels, and so influence glutamatergic functions in the NS (13, 14, 17). A relatively recently proposed mechanism thought to induce neurotoxicity via environmental chemicals, is endocrine disruption. Endocrine disruption is believed to be a crucial mechanism of most neurotoxicants, including metals, solvents, pesticides, Polychlorinated Biphenyls (PCBs), Diethylstilbesterol (DES), etc (21-25). Endocrine disrupting chemicals act by mimicking, enhancing, or antagonising the effects of endogenous oestrogens and androgens (21, 22). Their actions can result in alterations to hormone synthesis and/or release, altered transport and clearance of hormones, altered binding of hormones to their receptors (by binding themselves, thereby either mimicking hormone response, or blocking hormonal activation (24)), or altering components of pathways following receptor activation (22). An example of an endocrine disrupting mechanism is one used by lead, which lowers blood levels of testosterone, thereby de-masculinising certain areas of the male brain, and PCBs, which both mimic and antagonise various oestrogenic functions, and disturb production of androgens (21). As hormones are known to have a role in the development of the CNS, including sexual differentiation (26), disruption to their activities may result in disruption to the development of some brain areas, and the possibility of feminisation or masculinisation of particular brain areas (21-25). The neuroprotective function of hormones (discussed later) may also be hindered due to the endocrine disrupting actions of certain chemicals, allowing for their other neurotoxic mechanisms to have greater damaging effects. Neurotoxic investigations Carrying out investigations into the effects of neurotoxic chemicals is much more difficult in humans than it is in other animals, due to the greater difficulty in controlling the surrounding environment and its influences, and there are many potential variables that can have an effect on the overall result, in particular exposure to other environmental chemicals, drugs, alcohol, tobacco, education, culture, etc (27-31). All the potential confounding factors must be taken into consideration in order to analyse the neurotoxic effects only of the chemical in question (32). Often, environmental chemicals induce delayed neurotoxicity, whereby a patient does not present with symptoms until well after exposure to the chemical has ended, providing another problem to investigators (4). There are many different symptoms that can present upon neurotoxicity; migraines or headaches, confusion, memory loss, Multiple Sclerosis (MS)-like symptoms, problems with sleep, balance and hearing, attention impairment and trouble concentrating, anxiety and depression (8). Alterations to cognitive function, motor function and behaviour are common outcomes of neurotoxicity, and are a useful assessment of the effects of exposure to chemicals (32, 33). There are a wide range of different tests commonly used to assess neurotoxicity to the PNS and CNS (4, 32, 33). Measurements of functions such as motor reflexes, insensitivity to pinpricks on the skin, or impairment of sensitivity to temperature and vibration, provide evidence of PNS toxicity (4, 32, 33). Other functional tests, including IQ (Intelligence Quotient) tests, memory tests, assessment of mood and personality, and behavioural questionnaires, are used to assess toxicity to the CNS (4, 32, 33). Damage to the Nervous System can also be established by use of various brain imaging techniques (e.g. Computed Tomography, Magnetic Resonance Imaging) (9). These are useful in observing physical alterations to brain size and appearance caused by brain tissue atrophy following neurotoxic exposure (9). It is also possible, using these images, to ascertain which regions of the brain are particularly affected (9, 33-35). Despite the large quantity of literature outlining investigations concerning exposure to different neurotoxic chemicals, there are relatively few publications available that have identified a difference in response between males and females. Differences between susceptibilities of a range of age groups, and groups with varying levels of exposure, have been acknowledged frequently (27, 36-38), however reports are rare in which results for men and women are assessed independently, therefore it is often difficult to determine any differences in susceptibility between the sexes. Many reports record numbers of each sex taking part in the study, and match controls accordingly, then proceed to analyse results as a whole (27, 28, 39-45). Others exclude female subjects altogether, rather than including analysis of female results, but separate from the male (29, 30, 46-51). This is often the case when the number of female subjects is small compared to men. However, the results could still be analysed, and any differences between them could be noted. Some fail to establish which sexes have been used at all (52-54). Nevertheless, there is evidence from a number of reports, of a difference between genders in neurological functioning following exposure to neurotoxic chemicals. An extensive search using MEDLINE and EMBASE, of published studies and case reports into neurotoxicity of environmental chemicals, identified a number of studies which observed differences between males and females. For the purpose of this report, only those chemicals with gender differences have been mentioned. Evidence of Gender Differences in neurological outcomes of exposure to Neurotoxic Chemicals Metals There are roughly 40 different metals that exist in the environment, some of which are essential for life to occur (e.g. copper, zinc, etc), others which arent (e.g. mercury, lead, etc) (9). Exposure to metals in the environment has been known to cause adverse effects to both the adult and child human NS for many years (3). The neurotoxic effects of these metals are particularly well characterised, and have been well investigated. Included in this report are three of the major neurotoxic metals, of which there has been much exposure to in the environment, and of which there has been some indication of a sex difference in susceptibility to neurotoxic effects; mercury, lead and manganese. These three metals have been more extensively investigated than others, and therefore sex differences observed should not be ruled out of others, and may also be noted if they are as well examined. Mercury Mercury can take various different forms, each of which has distinct effects on human systems (18). Methylmercury (e.g. contaminated seafood), ethylmercury (e.g. Thimerosol, a component of some vaccines), elemental Mercury (present in industrial vapours), and inorganic mercury compounds (e.g. skin lightening creams) (18). Of these forms, methylmercury has been acknowledged as having the greatest detrimental effect on the correct functioning of the human NS, and in particular, the developing nervous system of children (18). In adults, methylmercury is thought to damage specific brain regions, such as the visual cortex, and parts of the cerebellum, whereas in children, as the NS is not completely developed, the effects are thought to be more widespread (7). It has been observed in a number of studies that male children show greater impairments in NS functioning following exposure than female children. In certain neurological tests, which have an association with methylmercury exposure, namely those assessing finger tapping, tendon reflexes, and leg coordination ability, males achieve poorer results (8, 36, 37, 55-57). As the majority of studies reporting results individually for male and female subjects are those carried out in children, the main sex differences reported here have been observed in children. However, similar results are noted in those adult investigations where males and females were analysed separately (27). McKeowyn-Eyssen et al. (1983), Cordier et al. (2002), Myers et al. (2003), Grandjean et al. (1998), and Marsh et al. (1987), all carried out numerous different tests on school children exposed to methylmercury at varying concentrations, pre- and post-natally. Each of these groups identified that, for those tests which have been shown to be more affected by increasing methylmercury levels, including finger-tapping, abnormal muscle tone, tendon reflexes, and leg coordination, male children showed poorer results (19, 57-60). McKeowyn-Eyssen et al. (1983) carried out the same tests on adults, and found an indication of a similar sex difference, with men being more likely than women to develop neurological disorders, following increases in methylmercury levels (37). Davidson et al. (2000) found that male, but not female, responses in neurological tests increased with methylmercury exposure, which is the opposite of the expected results, however, numerous unexamined variables were identified, which could have had influences on the results of the tests (31). Holmes et al. (2003) identified a link between mercury exposure and autism in children. Higher mercury levels in the hair were found to be associated with milder autistic symptoms (61). Perhaps because those children with milder symptoms were more able to excrete the mercury through their hair, before too much damage occurred. There was a greater number of females showing milder autistic symptoms, and a greater number of males showing severe autistic symptoms (61). From the evidence put forward here, there is a definite implication of a greater susceptibility for males than females to the neurotoxic effects of methylmercury exposure. There is an increased risk of neurotoxicity for children of women with increased levels of mercury in the hair (61). Hair mercury levels in subjects themselves, following equal exposure between the sexes, has been observed on numerous occasions as being lower in males than females, when associated with neurological problems (37, 61, 62). It may be that females have a better ability to excrete mercury through the hair than males, so less is present in body tissues. Lead Lead has long been known as a neurotoxicant, and its widespread release into the environment over the years has resulted in many neurological problems, mainly linked to learning difficulties (17), that have been well studied and characterised (3). Lead toxicity is thought to occur mainly in the hippocampus, cerebellum, and prefrontal cerebral cortex and again, it is thought that children, with their NS still developing, are at greatest risk to the neurotoxic insults of lead (7), so the majority of reports found here have been carried out in children. The elimination of lead from many environmental sources, such as motor vehicle petrol, and paints, has seen a decline in the amount of toxic lead exposure (7). However, it is still a problem in many areas, for example those homes where lead paint has been used in decoration (17). There are a number of studies that have reported a difference in cognitive impairments between male and female children. Tests carried out on school children, in South America, the UK and USA (38, 63-66), all identify a larger correlation between lead levels in the blood and poor cognitive ability in males than in females, while Wasserman et al. (1998) state that mothers reported behavioural problems with male children exposed to lead, more often than with exposed female children (67). An assessment of behavioural problems associated with lead exposure in American children (68) and an assessment of intelligence of children following lead exposure in Port Pirie (69), identified no difference between males and females in the results of their tests, while an assessment of the capabilities of children in school, and association with lead exposure (70), along with another investigation of child IQ by Needleman et al. (71), observed results to suggest females were more susceptible to lead neurotoxicity than male subjects, as they appeared to have greater prevalence of learning difficulties associated with lead. So, there appears to be a significant amount of evidence implying a gender difference in neurotoxicity associated with lead exposure. The majority of reports imply an increased susceptibility for males; however it is important for groups to look at sex differences in future studies, in order to ascertain conclusive results. This evidence also provides a need for investigation of sex differences in effects of lead exposure in adults. Manganese Manganese is another commonly used metal that can cause a toxic effect the NS upon exposure (20, 29, 40, 46, 47). There is a risk of manganese toxicity in various professions, in particular, welding (29, 46), but also through drinking or washing in water containing extraordinarily high levels of manganese (20, 40). There are a large number of reports confirming the neurotoxicity of manganese (20). Investigations have shown decreased intellectual ability in children over-exposed to manganese (40), and mood disturbances in men exposed occupationally (e.g. welders, factory workers.) (29, 40, 46, 47). In children, a report into an association between hair manganese levels and prevalence of hyperactivity, found that while there was a higher amount of manganese present in girls than boys, no difference was found between the sexes in assessment of neurological behaviour tests (72). Perhaps female brains are better able to cope with a higher amount of manganese. In adults, Dietz et al. (2001) found that a relationship between levels of manganese exposure and its effect on the Globus Pallidus area of the brain was seen only in men. These investigators give the reason that female workers have lower blood concentrations of manganese, and have a lower cumulative exposure index (73). However, they do not state whether there was a difference in actual exposure between sexes. If the exposure levels were the same, this could be an indication of increased susceptibility to males. In another study, results of neurological tests following manganese exposure were poorer for men than for women (74). As the majority of studies on manganese actually exclude females from results, or do not give separate results for each sex, it is difficult to make any definite assumptions about gender differences in neurotoxicity susceptibility. Implications from the three studies above provide a suggestion of a sex differences in manganese toxicity, with a greater effect within males. However, in future studies, where possible, females should be included, and the results analysed separately, in order to establish conclusive evidence for sex differences in neurotoxicity to manganese. Solvents There is a vast array of solvents that are used in many different industries and work places, meaning daily exposure for many different workers, including hairdressers, laboratory workers, painters, dry cleaners, and carpet layers, among others (33, 75-78). Due to the composition of solvents, they are particularly dangerous to the tissues of the NS. They are lipophillic compounds, and therefore have strong affinity for tissues rich in lipids, including the brain (33, 79). It is thought that psychomotor performance is the most common deficit (51) of solvent exposure, and prolonged exposure can cause permanent damage (15). Other symptoms include anxiety, insomnia, irritability, memory loss, fatigue and seizures (15, 33, 75). Solvent substances most often consist of a mixture of different chemicals, which can affect different regions of the brain. This can result in difficulties determining the toxic effects of a particular chemical (9). There have been many studies published that report clear association between solvent exposure and neurological deficits. Nelson et al. (1994) report that solvent exposure in workers at an automobile assembly plant, correlates with increased neurological disease, and, noticed in particular, an association with increased prevalence of a condition closely resembling MS (52). Cavalleri et al. (1994) obtained results to indicate deterioration of colour vision in factory workers following perchloroethylene exposure, even at low levels (53), and Boor et al. (1977) confirm a damaging effect of toluene on the CNS (54), a chemical that is also known to effect CNS development prenatally (3). Alcohol (Ethanol) is a major environmental solvent, although exposure rarely occurs occupationally, and it is most often taken in voluntarily (3). Hommer et al. (2001) studied the brain volumes of alcoholic and non-alcoholic men and women, and found that alcoholics had a much smaller volume of grey matter than non-alcoholics. This difference was found to be much more significant in females than males, suggesting an increased susceptibility of females to neurotoxic effects of alcoholism (34). In contrast, Pfefferbaum et al. (2001), in the same journal publication, indicated that the results of their study into alcohol effects on brain structure, show larger cortical sulci and lateral and third ventricles found in the alcoholics compared to non-alcoholics, which was a much greater and more significant difference in male subjects than female subjects. They also note that female brains show quicker and more effective recovery than those of males during abstinence (35). Jacobson (1986) ca rried out a study examining the brains of male and female alcoholics compared to non-alcoholic controls. It was noticed that the appearance of the brains on a CT scan was different between alcoholics and controls. Also observed was the fact that females appear more susceptible to structural changes in the brain following chronic alcohol intake, but are much more effective at recovering following cessation of intake, and the recovery occurs much quicker (80). Taking these 3 reports into consideration, there may be a difference in susceptibility of particular brain areas in males and females; however, females consistently recover more quickly from damage than males, indicating perhaps, a decreased susceptibility to long term damage. Neurophysiological deficits have also been reported in numerous studies of children exposed to alcohol pre-natally (81-83). However, few have noted results separately for male and female children. Nanson and Hiscock (1990) observed that female Fetal Alcohol Syndrome (FAS) children appear to have a higher IQ than males with FAS (83). As mentioned above, the majority of studies into other solvents, such as toluene, trichloroethene, n-hexane, chlorinated solvents (84), and solvent mixtures (49, 50, 76, 78, 85) in the workplace, report an obvious detrimental effect on the CNS, PNS, or both, following exposure. However, the majority included only men in the reports, or male and female results were analysed together. Again, it has been observed that the developing NS is especially susceptible to the neurotoxic effects of solvents, due to their high affinities for the brains lipid tissues (33, 79), and the BBB not being fully formed (7). Laslo-Baker et al. (2004) and Till et al. (2001) carried out studies on organic solvent exposure in pregnant women, taken in accidentally from occupational exposure, and the effects on neurodevelopment of their offspring. Both groups confirmed that children exposed pre-natally had poorer cognitive functioning than those not exposed, with lower results in neurological tests (75, 86). Again, no distinction was made between results for female and male children. Considering the obvious effects of solvents, including alcohol and toluene, on the NS, and the observations of sex differences from other neurotoxins, and the implications of sex differences in effects of alcohol mentioned here, it should be suggested that future studies automatically investigate male and female results separately, and allow for observation of any differences in results. Pesticides The term pesticides encompasses a wide range of chemicals, commonly used within a wide range of industries, particularly agriculture (87, 88). Included are the sub-groups; organophosphates, organochlorines, fumigants, and herbicides, all of which act to damage the NS of an organism, either directly, or via alteration of the cellular mechanisms that support it (87). Pesticides cause concern for human health as they are extremely widely used, and so readily released into the environment (88). It has been known for a long time that exposure to certain levels of these chemicals will adversely affect the human NS, as well as those organisms they are designed against (87, 88). Indeed, numerous studies have linked exposure to various pesticides with a number of neurological disorders, including Parkinsons disease (87, 89). In a similar situation to that for metals and solvents, there are many publications from groups investigating the effects of pesticide exposure on the human Nervous System, using an array of cognitive and neurobehavioural tests, with almost every study confirming the presence of some form of Neurotoxicity in subjects exposed to a range of doses. The following reports have identified separate results for neurological effects of pesticide exposure on male and female subjects, and an apparent greater effect on males. A report investigating the influence on the onset of Parkinsons and Alzheimers Diseases in elderly people living in the south of France, where pesticides are used daily in vineyards, noted a significant association between these disorders and pesticide exposure, in males only (90), suggesting a potentially increased susceptibility to males. Stallones et al. (2002) acknowledge males being at increased risk of developing neurological problems related to pesticide exposure than females, in an investigation into farmers, and their families in Colorado, USA (91), with the percentage of illnesses caused by exposure to pesticides almost three times greater in males. An assessment of neurobehavioural activity of Hispanic agricultural workers (92) identified a significant difference between the genders on results for 2 out of 10 tests, with females scoring lower than males. In the remaining tests, no significant differences were found between the sexes, although all exposed subjects faired worse than control, non-exposed (92). Similarly, pesticide-exposed Ecuadorians achieved lower outcomes in neurobehavioural tasks set by Cole et al. than did non-rural, unexposed Ecuadorians, and females were found to respond better in one task, with no significant difference between genders in others (93, 94). Guillette et al. (1998), carried out an assessment of Preschool children in Mexico, exposed to pesticides through living in close proximity of farm land. They identified a significant difference between those exposed and those living further away from the farm lands, with females performing better than males in several of the neurological tests (95). It appears that when there is a gender difference observed in the neurotoxic effects of pesticides, females tend to fair better than males, implying an increased susceptibility of males to the influences of pesticides on the NS. As it is more commonly males that are in the closest proximity to pesticides, within farming industries in particular, this could have some influence on this hypothesis. However, as the differences are also apparent in male and female children, with equal exposure, it does indicate a greater risk for males. The finding that there was only a significant difference in some tests may indicate an increased susceptibility of some brain areas in males over others, which correlates with results of studies of alcohol and tobacco smoke (below). Other Sources of Environmental Neurotoxicity Tobacco Smoke The chemicals contained in tobacco smoke, particularly nicotine, are now known to cause a variety of neurological problems, in addition to their other effects, including behavioural and cognitive problems during development, tremor, and an increased risk of stroke, from both smoking directly, and through passive smoke; inhalation or exposure prenatally (96-100). Various groups investigating toxicity caused by intake of tobacco smoke have described minor sex difference in the neurological outcome. Louis (2007) reports that, when looking into hand tremor as an outcome of tobacco smoking, the difference in score between smokers and non-smokers is greater in women than in men, which would indicate more of a susceptibility to women, rather than men (96). Jacobsen et al. (2007) investigated auditory and visual attention in adolescent smokers and non-smokers, with and without prenatal exposure to tobacco (101). They observed that different areas of the brain are apparently affected differently in male and female subjects exposed to tobacco smoke. In females, both auditory and visual attentions appear equally vulnerable, performing slightly more poorly in visual tests than males, while in males, auditory attention seems significantly more affected than visual attention, and in this auditory test, males performed substantially worse than females (101). The results of this investigation, put together with those from the Louis (2007) report, point towards sex-specific variation Gender Differences in Neurotoxicity Gender Differences in Neurotoxicity Abstract Neurotoxicity is damage to the structure and/or function of the peripheral and central nervous systems. It is a common outcome of exposure to hundreds of environmental chemicals, which act via a wide range of mechanisms. Due to the fundamental importance of the nervous system to a fully functioning body, the neurotoxic effects of many chemicals have been well investigated. There is evidence from a number of studies of a difference in susceptibility to environmental neurotoxins between genders. Males appear to be more vulnerable than females. There may be many reasons for this difference, a key one being the neuroprotective activities of the gonadal (sex) hormones, which differ between males and females. The female hormone, oestrogen, is thought to have greater protective activity, from a wide range of chemicals than the male hormone, testosterone. This report will examine the available evidence of a gender difference in susceptibility to environmental neurotoxins, and look into the actions of hormones within the nervous system as one of the main reasons for this difference. Introduction The nervous system (NS) is a fundamental component of a fully functioning human body. Due to the immense importance of the NS, any damage that occurs to this system will have huge repercussions throughout the whole body. Unfortunately, the NS is extremely vulnerable, and neurons, with their unique shape, and long, thin extensions protruding from their cell bodies, are highly susceptible to degeneration, from ageing and from exogenous substances (1, 2). It has been observed that exposure to a range of different environmental chemicals can have adverse effects on the NS, resulting in degeneration of neurons, and leading to onset of various neurological diseases (2, 3). The developing NS in particular is extremely sensitive to the effects of such chemicals (2, 4). Prenatal, and early postnatal, exposure to environmental chemicals, such as lead and those in tobacco smoke, can affect the developmental process within the Central Nervous System (CNS). This can lead to slowed and incorrect development, and neurological problems in the early years of life (4). From both animal studies, and human case reports of inadvertent exposures, there is also evidence to suggest a difference between males and females in their susceptibilities to neurotoxicity of some environmental chemicals (5). There are a number of reasons why this may be, including differences in amounts and activities of metabolic enzymes, differences in rates of absorption between the sexes, different rates of clearance of exogenous substances from the body, and differences in exposure to neurotoxic chemicals; diet, hobbies, occupations, etc (6). However, a key reason may be the neuroprotection that is conferred by gonadal hormones, and their metabolites, within the NS (5). The aim of this report is to research evidence of sex differences in responses to environmental chemicals, and investigate hormonal influences as one of the reasons for this difference. Neurotoxicity of Environmental Chemicals Neurotoxicity is a term used to describe damage to the structure and/or function of the peripheral NS (PNS) and CNS, brought about by exposure to particular exogenous substances (7, 8), which act via a range of mechanisms to induce cellular changes, and often cell death (7). Neurotoxicity can be seen in all ages of individuals exposed to hazardous chemicals, however, the developing NS is particularly vulnerable to their effects (2, 4, 7). Development of the NS involves a series of very specific steps, over a prolonged time period, each one occurring only when the previous is finished, and disruption to these events leads to incorrect development and neurological problems (4). The blood-brain barrier (BBB), which prevents many substances from passing to the brain, is not fully complete until several months of age, leaving the NS susceptible to damage (7). The entire NS is not fully mature until puberty (4). A great number of the reports published concerning neurotoxic effects of chemi cals have reported observations on child subjects. This is due to the fact that the developing NS is much more vulnerable, and so the neurotoxic effects may be more easily noticed. There are over 200 chemicals that have been confirmed as neurotoxic to humans (and other animals)as a result of exposure to them (3). A number of these chemicals are identified in Panel 1 (3), and can be divided into groups; metals, organic solvents, pesticides, and other neurotoxic chemicals. Panel 1. There are over 200 chemicals known to cause neurotoxicity in humans. This list identifies some common ones. Adapted from (3). Chemicals in bold and red are those identified within this report. Different toxins have distinct mechanisms through which they influence the NS. This depends on dose, route and duration of exposure (9). Those chemicals which are most widespread in the environment, and those which cause the most drastic effects, have been extensively investigated, and many of the mechanisms causing neurotoxicity have been identified (9). Given the knowledge of these effects, it is important to investigate the possible neurotoxic influences of the large number of other chemicals prevalent in the environment. Mechanisms of neurotoxicity The main mechanisms encompassed by the afore-mentioned groups of substances include; induction of oxidative stress, alterations to neurotransmitter synthesis including inhibition of synaptic signalling, accumulation of the substance within mitochondria leading to dysfunction, alterations to the flow of ions across neuronal membranes, activation of second messengers to induce apoptosis or inhibit neurogenesis, disruption of DNA/RNA, affecting the differentiation and functioning of glial cells, to indirectly influence neuronal cells, alterations to membrane fluidity, abnormal expression of neurotrophic factors (7, 10-20). There is a requirement for metals in many body processes, including within the NS, providing an additional mechanism by which exogenous metals can induce neurotoxicity (17). They can compete with essential metals for protein binding sites and influence cellular processes (17). For example, lead competes with zinc, which is known to have binding sites present in many important receptor channels, such as the N-methyl-D-aspartate (NMDA) receptor involved in glutamate signalling at the synapse. Lead can displace zinc, and therefore alter functioning of these channels, and so influence glutamatergic functions in the NS (13, 14, 17). A relatively recently proposed mechanism thought to induce neurotoxicity via environmental chemicals, is endocrine disruption. Endocrine disruption is believed to be a crucial mechanism of most neurotoxicants, including metals, solvents, pesticides, Polychlorinated Biphenyls (PCBs), Diethylstilbesterol (DES), etc (21-25). Endocrine disrupting chemicals act by mimicking, enhancing, or antagonising the effects of endogenous oestrogens and androgens (21, 22). Their actions can result in alterations to hormone synthesis and/or release, altered transport and clearance of hormones, altered binding of hormones to their receptors (by binding themselves, thereby either mimicking hormone response, or blocking hormonal activation (24)), or altering components of pathways following receptor activation (22). An example of an endocrine disrupting mechanism is one used by lead, which lowers blood levels of testosterone, thereby de-masculinising certain areas of the male brain, and PCBs, which both mimic and antagonise various oestrogenic functions, and disturb production of androgens (21). As hormones are known to have a role in the development of the CNS, including sexual differentiation (26), disruption to their activities may result in disruption to the development of some brain areas, and the possibility of feminisation or masculinisation of particular brain areas (21-25). The neuroprotective function of hormones (discussed later) may also be hindered due to the endocrine disrupting actions of certain chemicals, allowing for their other neurotoxic mechanisms to have greater damaging effects. Neurotoxic investigations Carrying out investigations into the effects of neurotoxic chemicals is much more difficult in humans than it is in other animals, due to the greater difficulty in controlling the surrounding environment and its influences, and there are many potential variables that can have an effect on the overall result, in particular exposure to other environmental chemicals, drugs, alcohol, tobacco, education, culture, etc (27-31). All the potential confounding factors must be taken into consideration in order to analyse the neurotoxic effects only of the chemical in question (32). Often, environmental chemicals induce delayed neurotoxicity, whereby a patient does not present with symptoms until well after exposure to the chemical has ended, providing another problem to investigators (4). There are many different symptoms that can present upon neurotoxicity; migraines or headaches, confusion, memory loss, Multiple Sclerosis (MS)-like symptoms, problems with sleep, balance and hearing, attention impairment and trouble concentrating, anxiety and depression (8). Alterations to cognitive function, motor function and behaviour are common outcomes of neurotoxicity, and are a useful assessment of the effects of exposure to chemicals (32, 33). There are a wide range of different tests commonly used to assess neurotoxicity to the PNS and CNS (4, 32, 33). Measurements of functions such as motor reflexes, insensitivity to pinpricks on the skin, or impairment of sensitivity to temperature and vibration, provide evidence of PNS toxicity (4, 32, 33). Other functional tests, including IQ (Intelligence Quotient) tests, memory tests, assessment of mood and personality, and behavioural questionnaires, are used to assess toxicity to the CNS (4, 32, 33). Damage to the Nervous System can also be established by use of various brain imaging techniques (e.g. Computed Tomography, Magnetic Resonance Imaging) (9). These are useful in observing physical alterations to brain size and appearance caused by brain tissue atrophy following neurotoxic exposure (9). It is also possible, using these images, to ascertain which regions of the brain are particularly affected (9, 33-35). Despite the large quantity of literature outlining investigations concerning exposure to different neurotoxic chemicals, there are relatively few publications available that have identified a difference in response between males and females. Differences between susceptibilities of a range of age groups, and groups with varying levels of exposure, have been acknowledged frequently (27, 36-38), however reports are rare in which results for men and women are assessed independently, therefore it is often difficult to determine any differences in susceptibility between the sexes. Many reports record numbers of each sex taking part in the study, and match controls accordingly, then proceed to analyse results as a whole (27, 28, 39-45). Others exclude female subjects altogether, rather than including analysis of female results, but separate from the male (29, 30, 46-51). This is often the case when the number of female subjects is small compared to men. However, the results could still be analysed, and any differences between them could be noted. Some fail to establish which sexes have been used at all (52-54). Nevertheless, there is evidence from a number of reports, of a difference between genders in neurological functioning following exposure to neurotoxic chemicals. An extensive search using MEDLINE and EMBASE, of published studies and case reports into neurotoxicity of environmental chemicals, identified a number of studies which observed differences between males and females. For the purpose of this report, only those chemicals with gender differences have been mentioned. Evidence of Gender Differences in neurological outcomes of exposure to Neurotoxic Chemicals Metals There are roughly 40 different metals that exist in the environment, some of which are essential for life to occur (e.g. copper, zinc, etc), others which arent (e.g. mercury, lead, etc) (9). Exposure to metals in the environment has been known to cause adverse effects to both the adult and child human NS for many years (3). The neurotoxic effects of these metals are particularly well characterised, and have been well investigated. Included in this report are three of the major neurotoxic metals, of which there has been much exposure to in the environment, and of which there has been some indication of a sex difference in susceptibility to neurotoxic effects; mercury, lead and manganese. These three metals have been more extensively investigated than others, and therefore sex differences observed should not be ruled out of others, and may also be noted if they are as well examined. Mercury Mercury can take various different forms, each of which has distinct effects on human systems (18). Methylmercury (e.g. contaminated seafood), ethylmercury (e.g. Thimerosol, a component of some vaccines), elemental Mercury (present in industrial vapours), and inorganic mercury compounds (e.g. skin lightening creams) (18). Of these forms, methylmercury has been acknowledged as having the greatest detrimental effect on the correct functioning of the human NS, and in particular, the developing nervous system of children (18). In adults, methylmercury is thought to damage specific brain regions, such as the visual cortex, and parts of the cerebellum, whereas in children, as the NS is not completely developed, the effects are thought to be more widespread (7). It has been observed in a number of studies that male children show greater impairments in NS functioning following exposure than female children. In certain neurological tests, which have an association with methylmercury exposure, namely those assessing finger tapping, tendon reflexes, and leg coordination ability, males achieve poorer results (8, 36, 37, 55-57). As the majority of studies reporting results individually for male and female subjects are those carried out in children, the main sex differences reported here have been observed in children. However, similar results are noted in those adult investigations where males and females were analysed separately (27). McKeowyn-Eyssen et al. (1983), Cordier et al. (2002), Myers et al. (2003), Grandjean et al. (1998), and Marsh et al. (1987), all carried out numerous different tests on school children exposed to methylmercury at varying concentrations, pre- and post-natally. Each of these groups identified that, for those tests which have been shown to be more affected by increasing methylmercury levels, including finger-tapping, abnormal muscle tone, tendon reflexes, and leg coordination, male children showed poorer results (19, 57-60). McKeowyn-Eyssen et al. (1983) carried out the same tests on adults, and found an indication of a similar sex difference, with men being more likely than women to develop neurological disorders, following increases in methylmercury levels (37). Davidson et al. (2000) found that male, but not female, responses in neurological tests increased with methylmercury exposure, which is the opposite of the expected results, however, numerous unexamined variables were identified, which could have had influences on the results of the tests (31). Holmes et al. (2003) identified a link between mercury exposure and autism in children. Higher mercury levels in the hair were found to be associated with milder autistic symptoms (61). Perhaps because those children with milder symptoms were more able to excrete the mercury through their hair, before too much damage occurred. There was a greater number of females showing milder autistic symptoms, and a greater number of males showing severe autistic symptoms (61). From the evidence put forward here, there is a definite implication of a greater susceptibility for males than females to the neurotoxic effects of methylmercury exposure. There is an increased risk of neurotoxicity for children of women with increased levels of mercury in the hair (61). Hair mercury levels in subjects themselves, following equal exposure between the sexes, has been observed on numerous occasions as being lower in males than females, when associated with neurological problems (37, 61, 62). It may be that females have a better ability to excrete mercury through the hair than males, so less is present in body tissues. Lead Lead has long been known as a neurotoxicant, and its widespread release into the environment over the years has resulted in many neurological problems, mainly linked to learning difficulties (17), that have been well studied and characterised (3). Lead toxicity is thought to occur mainly in the hippocampus, cerebellum, and prefrontal cerebral cortex and again, it is thought that children, with their NS still developing, are at greatest risk to the neurotoxic insults of lead (7), so the majority of reports found here have been carried out in children. The elimination of lead from many environmental sources, such as motor vehicle petrol, and paints, has seen a decline in the amount of toxic lead exposure (7). However, it is still a problem in many areas, for example those homes where lead paint has been used in decoration (17). There are a number of studies that have reported a difference in cognitive impairments between male and female children. Tests carried out on school children, in South America, the UK and USA (38, 63-66), all identify a larger correlation between lead levels in the blood and poor cognitive ability in males than in females, while Wasserman et al. (1998) state that mothers reported behavioural problems with male children exposed to lead, more often than with exposed female children (67). An assessment of behavioural problems associated with lead exposure in American children (68) and an assessment of intelligence of children following lead exposure in Port Pirie (69), identified no difference between males and females in the results of their tests, while an assessment of the capabilities of children in school, and association with lead exposure (70), along with another investigation of child IQ by Needleman et al. (71), observed results to suggest females were more susceptible to lead neurotoxicity than male subjects, as they appeared to have greater prevalence of learning difficulties associated with lead. So, there appears to be a significant amount of evidence implying a gender difference in neurotoxicity associated with lead exposure. The majority of reports imply an increased susceptibility for males; however it is important for groups to look at sex differences in future studies, in order to ascertain conclusive results. This evidence also provides a need for investigation of sex differences in effects of lead exposure in adults. Manganese Manganese is another commonly used metal that can cause a toxic effect the NS upon exposure (20, 29, 40, 46, 47). There is a risk of manganese toxicity in various professions, in particular, welding (29, 46), but also through drinking or washing in water containing extraordinarily high levels of manganese (20, 40). There are a large number of reports confirming the neurotoxicity of manganese (20). Investigations have shown decreased intellectual ability in children over-exposed to manganese (40), and mood disturbances in men exposed occupationally (e.g. welders, factory workers.) (29, 40, 46, 47). In children, a report into an association between hair manganese levels and prevalence of hyperactivity, found that while there was a higher amount of manganese present in girls than boys, no difference was found between the sexes in assessment of neurological behaviour tests (72). Perhaps female brains are better able to cope with a higher amount of manganese. In adults, Dietz et al. (2001) found that a relationship between levels of manganese exposure and its effect on the Globus Pallidus area of the brain was seen only in men. These investigators give the reason that female workers have lower blood concentrations of manganese, and have a lower cumulative exposure index (73). However, they do not state whether there was a difference in actual exposure between sexes. If the exposure levels were the same, this could be an indication of increased susceptibility to males. In another study, results of neurological tests following manganese exposure were poorer for men than for women (74). As the majority of studies on manganese actually exclude females from results, or do not give separate results for each sex, it is difficult to make any definite assumptions about gender differences in neurotoxicity susceptibility. Implications from the three studies above provide a suggestion of a sex differences in manganese toxicity, with a greater effect within males. However, in future studies, where possible, females should be included, and the results analysed separately, in order to establish conclusive evidence for sex differences in neurotoxicity to manganese. Solvents There is a vast array of solvents that are used in many different industries and work places, meaning daily exposure for many different workers, including hairdressers, laboratory workers, painters, dry cleaners, and carpet layers, among others (33, 75-78). Due to the composition of solvents, they are particularly dangerous to the tissues of the NS. They are lipophillic compounds, and therefore have strong affinity for tissues rich in lipids, including the brain (33, 79). It is thought that psychomotor performance is the most common deficit (51) of solvent exposure, and prolonged exposure can cause permanent damage (15). Other symptoms include anxiety, insomnia, irritability, memory loss, fatigue and seizures (15, 33, 75). Solvent substances most often consist of a mixture of different chemicals, which can affect different regions of the brain. This can result in difficulties determining the toxic effects of a particular chemical (9). There have been many studies published that report clear association between solvent exposure and neurological deficits. Nelson et al. (1994) report that solvent exposure in workers at an automobile assembly plant, correlates with increased neurological disease, and, noticed in particular, an association with increased prevalence of a condition closely resembling MS (52). Cavalleri et al. (1994) obtained results to indicate deterioration of colour vision in factory workers following perchloroethylene exposure, even at low levels (53), and Boor et al. (1977) confirm a damaging effect of toluene on the CNS (54), a chemical that is also known to effect CNS development prenatally (3). Alcohol (Ethanol) is a major environmental solvent, although exposure rarely occurs occupationally, and it is most often taken in voluntarily (3). Hommer et al. (2001) studied the brain volumes of alcoholic and non-alcoholic men and women, and found that alcoholics had a much smaller volume of grey matter than non-alcoholics. This difference was found to be much more significant in females than males, suggesting an increased susceptibility of females to neurotoxic effects of alcoholism (34). In contrast, Pfefferbaum et al. (2001), in the same journal publication, indicated that the results of their study into alcohol effects on brain structure, show larger cortical sulci and lateral and third ventricles found in the alcoholics compared to non-alcoholics, which was a much greater and more significant difference in male subjects than female subjects. They also note that female brains show quicker and more effective recovery than those of males during abstinence (35). Jacobson (1986) ca rried out a study examining the brains of male and female alcoholics compared to non-alcoholic controls. It was noticed that the appearance of the brains on a CT scan was different between alcoholics and controls. Also observed was the fact that females appear more susceptible to structural changes in the brain following chronic alcohol intake, but are much more effective at recovering following cessation of intake, and the recovery occurs much quicker (80). Taking these 3 reports into consideration, there may be a difference in susceptibility of particular brain areas in males and females; however, females consistently recover more quickly from damage than males, indicating perhaps, a decreased susceptibility to long term damage. Neurophysiological deficits have also been reported in numerous studies of children exposed to alcohol pre-natally (81-83). However, few have noted results separately for male and female children. Nanson and Hiscock (1990) observed that female Fetal Alcohol Syndrome (FAS) children appear to have a higher IQ than males with FAS (83). As mentioned above, the majority of studies into other solvents, such as toluene, trichloroethene, n-hexane, chlorinated solvents (84), and solvent mixtures (49, 50, 76, 78, 85) in the workplace, report an obvious detrimental effect on the CNS, PNS, or both, following exposure. However, the majority included only men in the reports, or male and female results were analysed together. Again, it has been observed that the developing NS is especially susceptible to the neurotoxic effects of solvents, due to their high affinities for the brains lipid tissues (33, 79), and the BBB not being fully formed (7). Laslo-Baker et al. (2004) and Till et al. (2001) carried out studies on organic solvent exposure in pregnant women, taken in accidentally from occupational exposure, and the effects on neurodevelopment of their offspring. Both groups confirmed that children exposed pre-natally had poorer cognitive functioning than those not exposed, with lower results in neurological tests (75, 86). Again, no distinction was made between results for female and male children. Considering the obvious effects of solvents, including alcohol and toluene, on the NS, and the observations of sex differences from other neurotoxins, and the implications of sex differences in effects of alcohol mentioned here, it should be suggested that future studies automatically investigate male and female results separately, and allow for observation of any differences in results. Pesticides The term pesticides encompasses a wide range of chemicals, commonly used within a wide range of industries, particularly agriculture (87, 88). Included are the sub-groups; organophosphates, organochlorines, fumigants, and herbicides, all of which act to damage the NS of an organism, either directly, or via alteration of the cellular mechanisms that support it (87). Pesticides cause concern for human health as they are extremely widely used, and so readily released into the environment (88). It has been known for a long time that exposure to certain levels of these chemicals will adversely affect the human NS, as well as those organisms they are designed against (87, 88). Indeed, numerous studies have linked exposure to various pesticides with a number of neurological disorders, including Parkinsons disease (87, 89). In a similar situation to that for metals and solvents, there are many publications from groups investigating the effects of pesticide exposure on the human Nervous System, using an array of cognitive and neurobehavioural tests, with almost every study confirming the presence of some form of Neurotoxicity in subjects exposed to a range of doses. The following reports have identified separate results for neurological effects of pesticide exposure on male and female subjects, and an apparent greater effect on males. A report investigating the influence on the onset of Parkinsons and Alzheimers Diseases in elderly people living in the south of France, where pesticides are used daily in vineyards, noted a significant association between these disorders and pesticide exposure, in males only (90), suggesting a potentially increased susceptibility to males. Stallones et al. (2002) acknowledge males being at increased risk of developing neurological problems related to pesticide exposure than females, in an investigation into farmers, and their families in Colorado, USA (91), with the percentage of illnesses caused by exposure to pesticides almost three times greater in males. An assessment of neurobehavioural activity of Hispanic agricultural workers (92) identified a significant difference between the genders on results for 2 out of 10 tests, with females scoring lower than males. In the remaining tests, no significant differences were found between the sexes, although all exposed subjects faired worse than control, non-exposed (92). Similarly, pesticide-exposed Ecuadorians achieved lower outcomes in neurobehavioural tasks set by Cole et al. than did non-rural, unexposed Ecuadorians, and females were found to respond better in one task, with no significant difference between genders in others (93, 94). Guillette et al. (1998), carried out an assessment of Preschool children in Mexico, exposed to pesticides through living in close proximity of farm land. They identified a significant difference between those exposed and those living further away from the farm lands, with females performing better than males in several of the neurological tests (95). It appears that when there is a gender difference observed in the neurotoxic effects of pesticides, females tend to fair better than males, implying an increased susceptibility of males to the influences of pesticides on the NS. As it is more commonly males that are in the closest proximity to pesticides, within farming industries in particular, this could have some influence on this hypothesis. However, as the differences are also apparent in male and female children, with equal exposure, it does indicate a greater risk for males. The finding that there was only a significant difference in some tests may indicate an increased susceptibility of some brain areas in males over others, which correlates with results of studies of alcohol and tobacco smoke (below). Other Sources of Environmental Neurotoxicity Tobacco Smoke The chemicals contained in tobacco smoke, particularly nicotine, are now known to cause a variety of neurological problems, in addition to their other effects, including behavioural and cognitive problems during development, tremor, and an increased risk of stroke, from both smoking directly, and through passive smoke; inhalation or exposure prenatally (96-100). Various groups investigating toxicity caused by intake of tobacco smoke have described minor sex difference in the neurological outcome. Louis (2007) reports that, when looking into hand tremor as an outcome of tobacco smoking, the difference in score between smokers and non-smokers is greater in women than in men, which would indicate more of a susceptibility to women, rather than men (96). Jacobsen et al. (2007) investigated auditory and visual attention in adolescent smokers and non-smokers, with and without prenatal exposure to tobacco (101). They observed that different areas of the brain are apparently affected differently in male and female subjects exposed to tobacco smoke. In females, both auditory and visual attentions appear equally vulnerable, performing slightly more poorly in visual tests than males, while in males, auditory attention seems significantly more affected than visual attention, and in this auditory test, males performed substantially worse than females (101). The results of this investigation, put together with those from the Louis (2007) report, point towards sex-specific variation

Flawed Characters of Young Goodman Brown, Rappaccinis Daughter, and The Birthmark :: Young Goodman Brown YGB

Flawed Characters of Young Goodman Brown, Rappaccini's Daughter, and The Birthmark      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   In many of Nathaniel Hawthorne's short stories, he creates characters with either a malicious or evil feature to relay to the reader a more allegorical meaning.   Many would say he targets woman without justification. Therefore a reader may interpret him to be a misogynist.   In the story " Rapaccinni's Daughter" he uses Beatrice as a carrier of a deadly poison.  Ã‚   In " Young Goodman Brown" he targets Faith as the character who is lost to the Devil. In the stories "Rappaccini's Daughter," and "The Birthmark," Hawthorne also uses men as transmitters of evil illicitly.   The men involved in the stories have their own flaws which contribute to the flaws of the women in their lives. Ultimately, Hawthorne in the cases above can be seen as a misogynist who directs his maliciousness on only women, yet he also uses male characters as vile transmitters of evil, therefore he is not a misogynist and targets both sexes equally.      Ã‚  Ã‚  Ã‚  Ã‚   In Young Goodman Brown, Faith, the wife of Young Goodman Brown is a character who loses her faith and submits to the Devil.   Hawthorne, in this case directly uses faith as the carrier of a flaw.   That is, she does not contain enough self-control, or faith to refuse the calling of the Devil.   Even with the emotional plea from her husband, "Look up to heaven, and resist the wicked one," (1590)   Faith cannot resist the Devil's temptation and has "uncertain sorrow," (1587) after submitting to him.  Ã‚   The character of Faith which Hawthorne portrays is one of uncertainty and one which has a lack of self control.   Faith is a good example of how Hawthorne uses a woman to symbolize a deeper significance, in this case, it is to evoke the hypocrisy of the Puritan people, that is, Puritans are really not as pure as we all think, they also contain evil characteristics, in this case, exploited at night. We cannot justify Hawthorne's usage of   Faith as misogyny, in that woman were not considered equal in status to men in the early 16th and later centuries.   Also, with the history of witchcraft during the puritan era, it can be seen appropriate that Hawthorne

The Human Experience

The Human Experience is a very touching movie. Throughout the movie we encounter all kinds of problems. There are many themes of forgiveness and healing in the movie. This movie is not only full of emotions, but it also helps you reflect on your life, and the actions we make as a humans. We find forgiveness and healing in our life’s by reflecting in our actions, and by taking action and actually trying to be better persons. In the movie we see all kinds of people in need of healing in their hearts. The two most common themes of healing we see in the movie are emotional and relational healing.Jeffrey Azize is in need of both emotional and relationship healing. When he was little his relationship with his father was not good. Jeffrey father was an alcoholic. Jeffrey remembers seeing his father more under the influence than sober. Jeffrey is in need of that love of his father. Jeffrey needs to learn how to forgive his father in order to have a better relationship with his father. At the end of the movie, we hear Jeffrey saying â€Å"Have you ever had a moment where you feel like everything is just right in the world? Time stops, and the stars are in line.It was the first time in a long time I could feel peace in my heart†. He felt at peace after going through all those experiences. He witnessed a lot, which made him forgive his father. He was able to heal. The Human Experience made me realize that there are bigger problems in our world. It taught me that I shouldn’t take anything for granted. Just like the homeless guy said â€Å"One day you might have a home, but the next day you might be on the streets†. This made me reflect on my life, it made me realize that I’m also in need of healing.It made me think of how ungrateful I am and how I never say thank you for the smallest thing. This movie taught me that I could make a difference, by doing something small like donating my time or donating things I don’t need to those wh o are in need. Overall this movie was amazing. I could watch it a million times, and every time it would have the same or bigger impact in my life. In my life I personally need a lot of healing. I’m in need of both emotional and relation healing. I’m one of those persons, who don’t forgive others.If you hurt me in some way I might say I forgive you but at the end I really won’t. I also have a lot of trust issues. It’s hard for me to trust someone, especially if they’ve hurt me before. For me trust is like a paper, once it’s crumble it can’t be perfect. I know that everything happens for a reason, but sometimes I wish I knew what that reason was. I guess that I need to learn how to forgive others, and to trust people. I need to open up more. Overall our society needs a lot of healing. Our society is really not acceptable.It makes me sad to see the way society is structured. Our society is truly ugly. The ugly truth about our soc iety is that no one cares unless you’re pretty or dying. Every day I ask myself what’s wrong with the world? We see that a lot of people are victims of our society, but we don’t do anything to change. Every 40 seconds, someone dies from suicide. Suicide is mostly seen among teens because they are being bullied for not looking or acting a certain way. Society no longer knows the meaning of beauty.It’s hard to grow up in a world where you never feel like you’re pretty enough. In this society you need to have designer clothing, you need to be size 0, you need to have a clean face, you need to wear makeup, you need to have perfect eye vision and perfect teeth; if you don’t then you’re automatically called ugly. We are the ones that are destroying our world. We are the ones bringing all that sin into this world. We all need emotional healing. We are in need of that love. Another kind of healing this society needs is that they need to accep t the way they are.Everyone is unique in this world. I see the world like a big food bowl; we are all different which makes things more interesting. We need to be happy with the way we look, and embrace it. Helping others is the best gift to help you heal. Helping others makes you realize that you should never take things for granted. By helping others I realized that doing something so simple like reading a book will bring a lot of smiles. Not only do you make someone smile but it also helps you reflect in your life. I have learned so many things about me by helping others.I learned about my trusting issues by helping others, and slowly I’m healing. Step by step I’m learning how to trust people. It’s not a big change, but in order to change you need to take small steps, and that’s exactly what I’m doing. My faith with God was shattered, but by healing I’m putting back the pieces together. I’m learning how to trust God, and leaving ev erything on his hands. I’m truly healing. Over all everyone needs healing. It’s not only me, but millions of others that are in need of healing.If you are not content with yourself, it’s obvious you need some kind of healing. If you can’t accept yourself, what makes you think that you can accept others? If you criticize yourself what makes you think that you won’t criticize others. In order for society to heal, we need to heal our soul firsts. By helping others, you realize your needs, It’s all a big circle. You need to help others, one you help them you see where you need healing, after healing yourself you realize that society needs healing, once you heal yourself you’re able to help society become better.

Artificial intelligence

Artificial intelligence Free Online Research Papers With all the different things in the world that change day by day, some can beone can encounter positive and some can be negative changes. Due to the fact of breakthroughs in Artificial Intelligence (AI), the effect on the job world and how National Aeronautics and Space Administration (NASA) contributes to the growth and positive reflection of Artificial Intelligence, it seems as though AI will definitely be a positive change. The future of the Artificial Intelligence is getting stronger and stronger as each day passes. With the unemployment rates still around 5.5% and decreasing from previous months, Artificial Intelligence is mostly a positive negative change on the outlook of the job market because of the advancement of technology. As NASA is the leading space aviator in the country, there is no one else fit to gain, boost moral and contribute towards AI. Artificial Intelligence will be one of the top technological necessities in the near future. As time, seasons, and technology change, so does the definition of Artificial Intelligence. â€Å"Artificial Intelligence, in light of this definition of intelligence, is simply the application of artificial or non-naturally occurring systems that use the knowledge-level to achieve goals† (Newell). The easiest definition to believe in is that AI is any machine that relates to a human if it’s through a program. Artificial Intelligence is â€Å"the ability of a computer or other machine to perform those activities that are normally thought to require intelligence† (Dictionary). Some machines were and are built to make our lives easier, keep us alive longer and stay healthy. â€Å"The only everyday ‘robots’ so far are things like car-building machines in Detroit, Sonys Aibo plastic dog, and mini-moon rovers that crawl through blast sites. Is the definition of the word robot ‘any machine that adjusts its own behavior according to feedback from its sensors?’ If so, thermostats, microwave ovens and light-sensitive patio lights are robots, too† (Pogue). With all the technological advancements everyday, Artificial Intelligence will improve over time. Artificial Intelligence is not just a machine that not only performs futile activities but can also provide useful help in lawenforcement, construction, cleaning, entertainment and medical services. The law Enforcement enforcement type is widely used as a robot that sees and moves into a territory to capture a video of the suspect or suspects. Another example of AI is used in law enforcement when Policeofficers get around streets, airports and sidewalks with the all newly invented Segway. With the use of the Segway, â€Å"You’re looking out above the crowd, you can see blocks ahead. It’s like you’re Shaquille O’Neal on wheels† (Mensching). Another type of military AI is Unmanned Air Vehicles (UAV) which has recently come to the front stage of research. These are small, lightweight devices that fly without operator control, thereby making them autonomous. Unmanned Air Vehicles are remotely piloted vehicles and robotic aircraft. They can be drastically cheaper to develop, build, and use than manned aircraft, which require sophisticated life support systems. With Artificial Intelligence being used to enforce laws, why not for construction? The answer is that it is already being used for construction with the back up of NASA. With multiple robots attacking one large pile of steel or any material it would be faster then if humans tried since the robots are stronger, smarter and group relating with all of the other robots. The Center Load behavior is activated when the force in the gimbal on either of the rovers exceeds a specified threshold. The corrective procedure, the lead rover performs its correction while the follow rover waits. When the lead rover has completed its correction, the rovers reverse and follow rover performs its correction. (RCC) You can’t seem to walk or drive anywhere without at least one person in a hurry. With the right equipment you now can vacuum your house when you’re on the go and shop at your favorite mall or sporting goods store. The Roomba is â€Å"a 3-inch-tall U.F.O.-like disc about a foot across now in red or blue with black accents that scuttles across floors and carpets, both sucking up dust and, with a spinning brush, whisking away bigger chunks of detritus. When it runs into something, it smartly rotates forty-five degrees and marches off in a different direction† (Pogue). Now with a robot that is considered Artificial Intelligence cleaning your floors for you while you’re not at home or near it, if that’s not amazing then what is? The next big type of breakthrough in Artificial Intelligence is that it’s being used to entertain humans all over the world. The aggressive progress of technology makes nearly every game a new beginning. Artificial Intelligence is very dependent on concrete details of the game environment. AI techniques can be applied to a variety of tasks in modern computer games. A game using networks to predict the players next move in order to pre-compute graphics may be on a high Artificial Intelligence level. Although AI must not always be real, the desire of Artificial Intelligence in computer games is primarily related to guiding non-player characters to make the game more entertaining. Yet another breakthrough in Artificial Intelligence is in the Medical medical field. With a surging elderly population in many countries throughout the world Artificial Intelligence will rise to unprecedented levels. â€Å"These advocates see robots serving not just as helperscarrying out simple chores and reminding patients to take their medicationbut also as companions, even if the machines can carry on only a semblance of a real dialogue† (Glick). The new addition for the elderly to live longer, stay healthy and be mobile through the use of robotics. The ideal results will be a major savings in medical costs, reduced burdens on the family and caretakers. Yasuyuki Toki, a researcher at NEC System Technologies, thinks emotional attachments to robots must be studied carefully. The future of Artificial Intelligence is in the hands of this generation and how it will impact the world. The world will not be the same today as in the futurewill not be the same in the future as today due to the technology boom, the creation, and ability to give AI â€Å"legal and ethical status to our here-and-now legal institutions† (Sokis). It has been said many times that by the year 2050 that our way of living and how we provide meals for holidays will drastically change due to AI. With the advancements of Artificial Intelligence â€Å"We will be sitting down to eat a synthetic turkey, with a robot helping out to prepare the trimmings† Jane Wakefield of BBC News Online states (Wakefield). There will also be information systems that will have real-time instructions that will monitor the cooking to make sure that it will not burn up like your Aunt’s meals every family gathering. By Christmas day 2050, through Artificial Intelligence, the atmosphere of the h oliday by Christmas 2050 it will all be all about the presents and nothing about the religious beliefs that have founded that surround the day. holiday. Some predictions for the future Christmas Christmas’s is are talking Barbie dolls which are able to respond to their owners and construction sets where the children will be able to design and build anything they put their minds to imagine.. With a new technology boom on the way and needed more then ever, it gives AI a great chance to experiment and develop some very useful and practical ideas for the near future. With the ability of purchasing groceries, clothes, automobiles and even houses in the luxury of your own home while wearing only your underwear is simply amazing because of the internet. The purchasing power of the internet has closely become a routine for many people all over the world. â€Å"When demand increases in one place, its consequences can be felt efficiently, and immediately, elsewhere. Wal-Mart led the way with it’s long-ago deal with Proctor Gamble automating shelf replenishment, but now that is also routine† (Kirkpatrick). The development of a program to distinguish what products need re-ordering and what products are expiring is impressive. Technology is not always a positive according to some people. As Mr. Heberling, a teacher at the local Webster Thomas High School and the head of the Science Olympiad team, has stated, that there a few negatives possibilities of Artificial Intelligence. In the interview with Mr. Heberling, the answer to the question of:I asked him how he saw AI in the future for himself. He responded, â€Å" â€Å"How do you see AI in the future for yourself? The answer was â€Å"A bad thing, because humans could eventually have the ability to lose control of the robot, whether they reason or not.† Mr. Heberling is not the only person who sees the advancement of Artificial Intelligence a negative issue. Another question asked to Mr. Heberling was,: Whatwhat are some concerns that you see with the advancement of AI? The output was, â€Å"Robots possibly and able to make decisions without human intervention, especially if biological.† Some say in the future robots will take us over and there is no way of stopping them. The ever so rise of machines will one day over power the ordinary job tasks that a few individuals think that are annoying and tidies. Even though â€Å"the aliveness’ into everything we do, and let electronic systems take over the dead, dull stuff, Samson says. winning Winning strategy for the information age is to inject ‘Richard Samson, author of the forthcoming book called ‘The Human Edge’, is convinced we are teetering on the precipice of an employment revolution for only the second time in modern history† (Crozier). The electronics revolution is a threat to the brain power of the human race. Many individuals have already been replaced by a machine. Take automobile manufacturing for instance,. The auto makers now have robots that do these jobs; paint the cars, weld, build assemblies, Computer Numerically Controlled (CNC) milling, assembly line functions and Armature winders. With all the jobs that humans once had getting thrown off to the side by the robot that will never stop unless broken, complain to the boss, take a break, and never walk away from the job. National Aeronautics and Space Administration (NASA) contributes to the growth and positive reflection of Artificial Intelligence with the donation of more then $666,000.00 each year towards For Inspiration and Recognition of Science and Technology (FIRST) to more than 111 teams and 5 events. The FIRST Robotics Competition is an exciting, multinational competition that teams professionals and young people to solve an engineering design problem in an intense and competitive way. The people at NASA also bring not only satellite broadcasts of the regional competitions and the nationals, but also the kickoff, which marks the start of a new season. NASA not only does the FIRST program but also the Botball program which gives students hands-on learning outside of the classroom to build and program a team of robots also project management skills that will prepare students for the workforce. NASA also has a Robotic Construction Crew that builds and constructs objects while computing with ot her robots. Many might ask what’s with all the talk about robots and Artificial Intelligence when we are not going to be taken over by an object that we have made? The answer is it that we have a chance to be taken over by robot might but, the realistic point as of today is that we will not be taken over by the creatures that we have developed happen and it might not happen; all we can do right now is wait and hope it doesn’t happen in the future. The future of AI looks bright and hopeful. While the breakthroughs are outstanding and don’t lack having the ability to do anything that we can put our minds to, AI is an endless supply of vast knowledge getting pout into a program to make our lives easier and better. Maybe in the future due to Artificial Intelligence we will be playing a sport on segways or a hovercraft type robot to score a point. The future could also lead to robots that will patrol our streets and keep the human police officers off the dangerous streets from be ing shot or dangerously injured. Possibly those same robots could be building our houses for us with out one single mistake or failure. It is not very hard notice once you walk through a well developed mall that you notice at least one video game store. The video game industry is a vast array of Artificial Intelligence that entertains people who enjoy sport games, first person shooters, role playing, and any other kind of video games. With all these people who enjoy video games, they will also enjoy all the different types of AI gifts for the holidays like a talking Barbie dolls which interact with their owners and construction sets that allow the user to build anything that will interact with the user. The medical purposes will let our mothers, grandmothers and pets live longer then they do. Artificial Intelligence will allow robots to keep an eye on our elderly and take care of them when needed. The effect of all this new technology to the world is mainly positive but also negativ e at the same time. Once we start replacing people at jobs with robots our unemployment rate will increase and will suffer a moderate depression even though the AI will also bring new jobs into the market. The only bad thing with the new jobs into the market is that the people who have lost the job will have to be re-educated and trained for the new jobs that interact with the robots that have taken over their job. Artificial Intelligence will be one of the top technological necessities in the near future because of all the breakthroughs, the increase on the job market, the inevitable technology boom, and all the contributions that the National Aeronautics and Space Administration bring to Artificial Intelligence. The world will be a better place and an excellent environment for future inventions, creatures, and even war now that Artificial Intelligence has an impact on how we will live and interact with the environment. As the technology boom declines we will be left with nothing t hat any person could have expected in return, a new outlook on life and how we see the world. Works Citied Crozier, Ry. â€Å"Rise of the Machines.† Electronic News.com. 14 Feb. 2005. Reed Business Information. 13 Feb. 2005 . Heberling, Charles. Personal interview. 11 Feb. 2005. Kirkpatrick, David. â€Å"The Real Boom.† 4 Dec. 2003. Fortune.com. 9 Feb. 2005 . Pogue, David. â€Å"The Robot Returns, Cleaning up.† 28 Aug. 2003. New York Times. 9 Jan. 2005 . â€Å"Robotic Construction Crew starts to work† robotslife.com 16 Jan. 2002 Robots Life. 9 Dec. 2004 â€Å"Robots seen as Companions for elderly.† AI Magazine Summer 2004, Vol. 25. Proquest. Webster Thomas High School, Thomas Library. 30 Nov. 2004 â€Å"SimCity used in AI experiment: new urban planning computers.† Computer Shopper Aug. 1992, Vol. 12. Pro Quest. Webster Thomas High School, Thomas Library. 30 Nov. 2004 Soskis, Benjamin. â€Å"Man and the Machines.† Legal Affairs. Jan/Feb. 2005. LegalAffairs.org. 3 Jan. 2005 . Wakefield, Jane. â€Å"Hi-Tech Ghosts of Christmas Future.† 25 Dec. 2002. BBC News. 12 Jan. 2005 . Websters Revised Unabridged Dictionary  © 1996, 1998 MICRAWith Christmas 2050 coming soon, how could all those vegetarian people not like the turkey that is cooked by your robot companion and is made of 0% real turkey? Research Papers on Artificial intelligenceBionic Assembly System: A New Concept of SelfPETSTEL analysis of IndiaHip-Hop is ArtOpen Architechture a white paperAnalysis of Ebay Expanding into AsiaComparison: Letter from Birmingham and CritoThe Project Managment Office SystemInfluences of Socio-Economic Status of Married MalesIncorporating Risk and Uncertainty Factor in CapitalTwilight of the UAW

Mall Observation Essays

Mall Observation Essays Mall Observation Paper Mall Observation Paper Shopping Mall Observation A sociological observation was conducted at Manhattan Village mall from 5:48 P. M. to 8:00 P. M. on Saturday, September 18, 2010. There were many different types of ethnicity and different ways of how people act. On the observation day, there were many people in groups of three or more. People tend to just worry about themselves and their own group. Many families brought little kids and let them play around the water fountain. People are so unique in so many ways such as different cultures, views, an d perceptions. In order to communicate and adapt to a new culture, people must learn to understand signs, norms, and social control. These three factors are important and touch almost every aspect of social life. According to Kerry Ferris and Jill Stein in The Real World: an introduction to sociology, a sign is â€Å"a symbol that stands for or conveys an ideaâ€Å"(101). Signs are price tag, a slow down sign, numbers, and etc. All signs convey information. Signs are the most common and they make everyone’s life a little easier. Gestures is an example of signs. Gestures are usually have to do with body movements. Even though signs are everywhere and all around, some people have to learn in order to understand what they represent. For example, during the mall observation, there were many sale signs outside of the stores. Those signs are very powerful because they attract customers and persuade them to come in. Sale has many meanings like what is on sale and how many percent off of that particular item. People are being tricked because these signs are big, easy to see, and outside of the stores. One couple walked by Gap store, they saw a sign saying, â€Å" 25% to 50% off on Summer Apparels†. They saw the sign so automatic their minds started to be curious and nosy. They went in, came out with one bag, and looked happy that they got a good deal. Another example was when the girl asked a security where to look for an elevator in Macys. She spoke broken English so the security showed her to look at the directions on top. These directions are signs and pictures to guide people. Signs are very important because some people would be lost without them. Norms are â€Å"the rules and guidelines regarding what kinds of behavior are acceptable and appropriate within a culture†(Ferris and Stein 104). According to Ferris and Stein, some norms are informal and formal. Informal norms are unspoken and formal norms are laws or rules. There are many norms that can’t be written but as humans being, people learned them quite well. To be specific, an informal norm in the mall would be standing in line to buy ice cream. People are waiting to buy ice cream patiently, no one is allow to cut in front of anybody. Another example of informal norm is invade people personal space. When walking around the mall, people are all scattered everywhere. Do not walk close to them or touch them because they will be irritated. Informal norms are no need to be written down because society teach people to follow it. As for formal norms, they are rules and laws. Formal norms are written down and expected to be follow. However, some people are going to break these rules or laws. Basically, everybody know that no pets are allow in the mall. There was a lady, probably in her early thirty, brought a dog and tried to hide it in her purse. Of course, the security caught her and asked her to leave the mall. She knew not to bring her dog in the mall but yet she did it anyways. Then another boy broke the rule by wearing a jacket with a hood in the mall. Hats, masks, and sweaters with hood are not allow. Everyone needs to show their face and not try to hide anything. The boy listened to the security and took off his hood. However, if the security sees that the boy puts the hood on again, then he has to leave the mall. These norms are important in the shopping mall because the mall should be a safe place for everyone to hang out. If there are no norms, people would trash the mall and the mall is no longer a safe place to hang out. Social control is â€Å"the formal and informal mechanisms used to increase conformity to values and norms and thus increase social cohesion†(Ferris and Stein 105). Everybody needs to follow and obey the rules or there will be consequences. However, social control is established by sanctions. According to Ferris and Stein, sanctions are â€Å" a means of enforcing norms†(105). There are positive and negative sanctions. Positive sanctions are approval such as handshake, smile, praise, or reward. Negative sanctions are disapproval like harsh words, fine, or even jail. Some examples of positive sanctions are when the employees greet and shake hands with the customers. Also, this one young girl picked up a piece of trash and put it in the trash can. The janitor came and said thanks. Some of the negative sanctions examples are when one little boy got asked if he took some candies. The boy was about ten year old and he took some candies from Godiva. Even though the security did not arrest him but the boy was ask to leave. The boy received some harsh words from the security. Also the lady brought her dog broke the rules so she has to be punished by leaving the mall. Social control and sanctions are important in a shopping mall because they give order and everyone must follow. Without social control and sanctions, people would do whatever they want and there will be chaos. This mall observation was a great learning experience. This world would be crazy and chaos if there are no signs, norms, and social control. People would disrespect one another and there would be no order. This observation was interesting because it gave knowledge about human social activity. All people are trying to obey rules and regulations. However, there will always be someone who breaks the rules in order to adapt to a new culture.

Marijuana Essay Example | Topics and Well Written Essays - 750 words - 1

Marijuana - Essay Example It also indicates that a large percentage of the individuals are regular users of the drug. I intend to use the source to demonstrate marijuana’s benefits in controlling anxiety. Ejelonu, Akudo. â€Å"How Does Marijuana Affect the Brain?† Serendip. 01 October 2008. Web. 31 July 2012. The article reviews ways in which marijuana affects people’s mental capacity. The author illustrates both positive and negative effects of the drug, including Marijuana’s medicinal value but focuses attention on marijuana’s effect on people’s ability to recall and how the drug influence emotions. Some of the drug’s components, according to the article, for example impair coordination among neurons in the brain to weaken a person’s cognitive ability upon consumption of the drug. The article also identifies factors that drive people into using marijuana, and secondary effects of marijuana among college students. While it identifies stress as the main cause of usage, the article explains that the drug sends the students into a state of uncontrollable emotions. It also explains that the stimulating impacts of the drug are temporary and users are able to regain their sober status once the drug wears out of the body. I will apply the article in exploring the existing debate on marijuana. Hogan, Julianna, Gonzalez, Adam, Howell, Ashley, Miller, Marcel, and Zvolensky, Michael. â€Å"Pain-related Anxiety and Marijuana Use Motives: A pilot Test Among Active Marijuana- using Young Adults.† Cognitive Behavior Therapy. 39. 4. 238- 292, 2010. The article seeks to investigate anxiety that is caused by pain as a factor that influences the use of marijuana. Based on an experimental research, the article identifies a significant relationship and concludes that pain motivates people to use marijuana. I will use the article to illustrate medicinal benefits of marijuana. National Institute of Drug Abuse. â€Å"How Does Marijuana Use Affect School, Work and Social Life?† Research Reports: Marijuana Abuse. 2010. Web. 31 July 2012. P. 1 The article reports on the impacts of marijuana on people’s lives. Based on existing literature, it explains that intoxication from marijuana lasts for a longer duration that the user experiences its stimulating effect. It further explains that the drug negatively affects academic performance of students who relies on its use. Similarly, it leads to drop out from academic institutions and lower rates of income in people who heavily rely on it as compared to those who do not. The article also associates the drug with other negative social conditions. I will use this source to highlight reasons for illegalization calls. Nida for Teens. â€Å"What are the Long-term Health Effects of Marijuana Use?† Nida For Teens. 2012. Web. 29 July 2012. P. 1 With the article’s aim of discussing ‘long-term’ impacts of marijuana usage, it identifies a reduced mental c apacity to comprehend complexities and coordinate body parts besides increasing a person’s vulnerability to some genetic diseases. The article also identifies addiction as a health risk factor of marijuana besides increasing a user’s risk of developing respiratory complications. Similarly, the article reports possibility of drug’s usage leading to use of other drug as well as its use as a medicine. I plan to use the article to

Big box stores vs mom and pop stores Assignment - 1

Big box stores vs mom and pop stores - Assignment Example Each restaurant offers something different than the other and so they are free to select whatever price they like for their products. Examples of Monopolies include public utilities like water, gas and electricity, cable TV, the local phone service companies. Important to note, that monopolies can exist in a market locally due to their geographical locations. Entry into a market where monopolies exist is quite difficult by new businesses since the large firms have larger market shares and there is not much left for the new companies in the market both in terms of buyers and profits. Competition is directly related to the methods and procedures by which the companies produce and sell their products. Different market structures are found in different industries which imply that there are different kinds of buyer to seller relations in every market. In a monopolist firm, they are able to increase or reduce the prices of their products (due to product differentiation), however, they cannot do so with full liberty, they have to abide by the unfriendly forces of the market. Sellers’ rivalry against each other involves sales-promotion costs along with the expenses of differentiating their products in order to attract customers. As a result, buyers get more variety in the products but in the long run the products prices involve the additional costs involved. Since the sellers in a monopolistic competitive market are not likely to be equally flourishing in their product policies and sales promotion, some of them will be successful in achieving profits exceeding t he basic interest on their investment, such profits will be earned from the buyers that have been attracted. (Karier, 241) The market and the monopolist’s demand curves are found to be the same. Demand of the monopoly is the demand of the industry and hence illustrated by a downward curve. However, the