Functional Role of Neurogenesis in Humans

Functional Role of Neurogenesis in Humans Self-renewing stem-like cells in the adult hippocampus have captured the imagination of neuroscientists and clinicians for decades. Unfortunately, there have been relatively few studies investigating the functional role of AHN in humans. Throughout this thesis, I have described a number of studies in which we undertook the challenge of identifying indirect correlates of AHN in humans as well as elucidating the functional role of adult-born granule cells in everyday memory. We accomplished this by assessing various lifestyle- and blood-based factors known to influence neurogenesis from the animal literature and comparing these factors to behavioural performance on tasks which tested the proposed roles for AHN in learning and memory. There has been much speculation regading the functional role of neurogenesis in humans. Computational modellers and theorists have proposed several distinct roles for AHN in cognition based on what is known of their location in the brain, functional connectivity with surrounding regions and physiological poperties. Some have proposed that the constant turnover of newborn cells in the hippocampus would allow memory storage for novel events, while avoiding interference with older memories, a computational process termed pattern separation (Becker et al., 2005; Chambers and Conroy, 2007; Appleby and Wiskott, 2009; Becker et al., 2009; Weisz and Argibay, 2009; Aimone and Gage, 2011). However, events occurring close together in time may be subject to enhanced interference because the same population of cells would be firing in response to each event encountered. This process of increasing interference between events occurring close together in time is referred to as pattern integration (A imone et al., 2006). Indeed, some studies have shown paradoxical improvements in working memory tasks following ablation of neurogenesis (Saxe et al., 2007). However, working memory circuits outside of the hippocampus may be responsible for such improvements. Across short timescales, the majority of behavioural evidence from rodents has actually demonstrated that the role for neurogenesis in cognition, although seemingly widespread, converges on one function in particular. The formation of context-shock associations is impaired in animals lacking neurogenesis (Saxe et al., 2006; Winocur et al., 2006; Imayoshi et al., 2008; Warner-Schmidt et al., 2008; Wojtowicz et al., 2008; Hernandez-Rabaza et al., 2009; Ko et al., 2009; Guo et al., 2011; Nakashiba et al., 2012; Pan et al., 2012b), especially when the shock is relatively weak or training paradigm relatively short (Drew et al., 2010; Pan et al., 2012a, 2013). Animals lacking neurogenesis are also impaired at discriminating between o verlapping odor pairs (Luu et al., 2012) or between nearby, but not far apart spatial locations (Clelland et al., 2009). In contrast, upregualting neurogenesis via aerobic exercise or genetic manipulation has been shown to increase AHN and leads to enhanced behavioural pattern separation or CFC performance (Creer et al., 2010; Sahay et al., 2011; Kohman et al., 2012). While it seems like a wide-variety of tasks require adult-born granule cells, many, if not all of these tasks require overcoming interference. All of these tasks require the animal to form separate representations of similar stimuli, regardless of whether the stimuli are different contexts, objects, spatial locations or odours. This is why I say that AHN is required for a wide-variety, yet specific set of memory tasks. The behavioural requirements of tasks shown to depend on neurogenesis have differed substantially, but the psychological construct shown to rely on AHN has been fairly consistent. Neurogenesis may further help separate similar events occurring over longer time periods (Becker, 2005; Aimone et al., 2006; Becker and Wojtowicz, 2007). A distinct pool of newborn neurons would help to add a degree of contextual novelty to similar events that are separated by a sufficient amount of time. Without new cells being added to the hippocampal network, the same populations of cells would end up reperesenting multiple different memories, leading to catastrophic interference (Wiskott et al., 2006). This account of the role for neurogenesis in learning and memory has generally been reffered to as the memory retention hypothesis throughout this thesis. In contrast, others have proposed that the addition of newborn cells to the hippocampus would result in existing connections being altered in such a way that information is lost (Feng et al., 2001; Deisseroth et al., 2004; Frankland et al., 2013). This account of the role for neurogenesis in learning and memory has generally been referred to as the memory clearance hypothesis throughout this thesis. Behavioural evidence from non-human animal studies has supported the memory retention hypothesis, especially for spatial or context-rich memories. For instance, rodents with ablated neurogenesis display marked deficits in remembering the platform locaton following MWM training across long, but not short timescales (Snyder et al., 2005; Deng et al., 2009; Jessberger et al., 2009; Kitamura et al., 2009; Inokuchi, 2011; Pan et al., 2012a, 2012b, 2013). In contrast, some studies have shown impaired long-term retention of fear memories in younger mice with relatively high rates of neurogenesis compared to their older counterparts (Akers et al., 2012). When older mice had wheel-running- or antidepressant drug-induced enhancement of neurogenesis, they were impaired on tests of remote memory compared to control mice (Akers et al., 2014). Therefore, it would seem that behavioural evidence from rodents has also supported the memory clearance hypothesis. The persistence or clearance of memories as a result of ongoing neural turnover in the DG may depend on the type of memory. There is evidence to suggest that spatial memories are always dependent on the hippocampus (Snyder et al., 2005; Deng et al., 2009; Jessberger et al., 2009). For these memories that are permanently hippocampal-dependent, AHN may help keep overlapping events disctinct from one another, thereby promoting long-term retention of the original memory. On the other hand, fear memories may be supported by regions outside of the hippocampus (Kitamura et al., 2009). Thus, for those memories that can be supported by extrahippocampal structures, AHN may accelerate the process of systems consolidation (Kitamura et al., 2009), shifting the dependence of the memory from the hippocampus to neocortical regions (McClelland et al., 1995; Squire and Alvarez, 1995; Maviel et al., 2004; Squire and Bayley, 2007). While animal studies have provided val uable clues as to the importance of AHN in learning and memory, it has nonetheless become apparent that studying the functional role of neurogenesis directly in humans is the critical next step that must be taken in order to alleviate some of the confusion generated in non-human animal studies. In the set of studies that comprise this thesis, we have demonstrated that change in aerobic capacity following chronic physical activity correlates with change in performance on a putatively neurogenesis-dependent visual pattern separation task. On the other hand, stress and depression scores had opposing effects on behavioural pattern separation performance. Importantly, neither exercise response nor depression scores predicted performance on other trial types within the BPS-O, repeated or novel items, nor the visuo-spatial CANTAB ® PAL task. We have also shown that lower stress and depression scores are associated with improved visual object recognition on repeated items following a two-week delay from the study phase. Further, on two-week delayed retention tests, participants scored near chance at identifying lures as â€Å"similar†, regardless of stress and depression levels. Interestingly, they more often misclassified these items as â€Å"new†, as opposed to â €Å"old†. Our results provide indirect evidence from human participants that AHN is important for pattern separation across shorter delays, while contributing to the persistence of memories for repeated items across extended time intervals. Future studies could explicitly test the memory clearance hypothesis in humans by measuring recognition memory across longer timescales with a pro-neurogenic intervention, such as long-term exercise, in between study and test. Pattern separation and memory retention (or clearance) may be coexisting phenomena. The addition of immature neurons to the hippocampus may at first bias the network towards pattern separation, as opposed to pattern completion, thereby reducing interference between events (Yassa and Reagh, 2013). In turn, the amount of pattern separation may decide what information will be subject to reconsolidation and what information will be cleared (Yassa and Reagh, 2013). Reconsolidation is the process whereby an existing memory becomes susceptible to change. If an event is considered similar, but not the same as, a previously stored event then the original memory may be modified to accommodate the discrepent information. Thus, the constant addition of adult-born neurons to the hippocampus may serve as a means of adding contextual information to existing memories. However, the original memory may be altered so drastically during reconsolidation that it is no longer accessible (essentially cleare d), depending on the amount of interference between the original memory and the novel event. Indeed, a number of computational models predict that the addition of newborn neurons to an existing circuit would hinder retrieval of previously stored memories (Deisseroth et al., 2004; Weisz and Argibay, 2009, 2012). On the other hand, if two events are considered one in the same, then information may be strengthened, although more generalized in nature. As these adult-born neurons that once contributed to pattern integration or pattern separation continue to mature and establish new synaptic connections with the pre-existing circuitry, they may destabilize previously established memories in the hippocampus, leading to the loss of previously stored information (Josselyn and Frankland, 2012; Frankland et al., 2013; Yassa and Reagh, 2013). In turn, the clearance of older memories would make room for new ones and the newborn neurons would become part of the physical storage site for new memo ries (Josselyn and Frankland, 2012). Thus, both processes may be beneficial in their own way. Whether or not memory clearance is a benefit or detriment to memory performance really depends on the relative importance of information is being cleared. Correlates of Neurogenesis in Humans and Animals Neurogenesis is down-regulated in a variety of neuropsychiatric disorders, so being able to characterize AHN in vivo is critical for better disease prevention and/or treatment. Unfortunately, there is no way to non-invasively quantify newborn cells in the living human hippocampus. Therefore, it has been difficult to improve our understanding of how neurogenesis influences the onset or recovery from certain disorders associated with downregulated neurogenesis, such as depression. In addition, we cannot assess the specific contribution of newborn neurons to learning and memory.

One Hundred Years of Solitude and The Woman in the Dunes Essay

Solitude can exist in many ways and can be present in any form in human beings. Each person is eventually alone deep inside themselves, which is why communication and connections are essential in life. In the novel One Hundred Years of Solitude by Gabriel Garcia Marquez and Kobo Abe's The Woman in the Dunes, solitude is one of the main dilemmas that the main characters in the novels encounter. In the novels, the main characters are perpetually looking for a way to defeat their loneliness in the world and in many cases try to find it through sexual intercourse. The patriarch Jose Arcadio Buendia, in One Hundred Years of Solitude, is the founder of Macondo. The location of Mocondo is significant as it sits on an isolated place which gives the sense of the Buendia family being surrounded by solitude. It also seems as if solitude is an inherited trait of the Buendia family leading to a pattern of incest, which was started by Jose Arcadio Buendia and his wife, who is also his first cousin, Ursula Iguaran. Sex is probably used in the novel as a way to somehow bond the family together. Sex can be used as a tool to make connections to one another and can create body language which can also be a way of communicating. We see this especially in the second generation of the family, when Colonel Aureliano Buendia has sex during the wars with seventeen different women (which he shows no sign of predilection towards). You can also deduce that he went on a journey to free himself from solitude and overall was unsuccessful as it was shown when he m ade an attempt to get with the adolescent "mulatto" girl enslaved by her grandmother. This shows an effort by one of the Buendia men to try to have a loving relationship with another char... ...here was no particular need to hurry about escaping." (239). Realizing his situation, he becomes one with the dunes and is able to live a purposeful life with the woman he once opposed living with. Without any type of sexual relationship, none of the characters in the novels One Hundred Years of Solitude by Gabriel Garcia Marquez and Kobo Abe's The Woman in the Dunes would have been explored thoroughly. Sex usually exposes a hidden hope or apprehension, desire and lust for something. In this case the characters of the novels lust, desire for identity and companionship, and is something they strive to acquire. In order to attain this, they attempt to use sex as a tool to triumph over solitude and gain communication and connection to reach one another. This is why sex is essential in providing two crucial things that are necessary in life to avoid solitude.

What type of man that girls are attracted to?

Kind and helpful men make women feel protected and safe. Friendly men are people who are easy to approach and make others feel comfortable. The reason why there are not so many women are attracted by artist men is because artists are sensitive and inconstant. It's hard to keep a relationship that both side need to be understand. And women always need loyalty from their boyfriends. Beyond good characteristics, men also need talents to attract women. Most women (31 said that men look cool when they play sports, 24% like men who can cook or make handmade things, 17% like men who play music, 13% like singers.But only 2% attracted by men who can make doll dress. Women like healthy men and playing sports Is the best way to show healthy and energetic. And nothing more romantic than eating a meal or receiving a gift made by your own boyfriends. Making dress or hat they were gays. Moreover, background is also a factor that should be mention. According to the result of some surveys that have b een carried out recently, one of the most important women often care about men is about their background: 83% people commit that they often take men's background under consideration while Just only 17% of them say that this is not important.In the past, women used to suffer from discrimination a lot. They were totally dependent on their husband without having any human rights or making decisions of their own. That is why men's background was not taken into inconsideration to women especially in under-developed countries. Apparently, men in today's life also hold different attitude toward the role of women, especially those for whom they are fall in love. It is believed that the track of conquering a girl's heart is a tough one. Not only is appearance critical point but also men's background.According to some recent surveys, women tend to pay attention to three aspects from a guy's background: family, education (occupation) and personality background. Among these criterion, women see m to focus mostly on the education base. From some statistics, 60% of women say a man's knowledge is the critical point in forming his future life, 25% of them care about men's characteristic and the rest want to know more about men's family. It is not strange that girls often have intention of studying about their boyfriends' family during dating stage.They may have questions about guys' parents including their Jobs, personality†¦ There are many people who have their own prejudice toward others. That is why keep dating with a boy whose family members make you feel uncomfortable is annoying. Unlike the old stage in which women do nothing but obey heir men as well as their families completely ,today's society allows women to have the right of choosing the most suitable man for them. The second idea is related to the education background of men. Currently, men are supposed to play the main part in the families.For households which women do not go to work, all of financial issues become men's loads. In case of undergraduate guys, girls need to know about their major, strong as well as weak points. Dating with an intelligent and hard- working boy seems to be more attractive than hanging out with a lazy one. Good man in modern life should also have great personality. This may seem an ambiguous aspect concerning men's background since each individual has his/her own characteristic that tend to be maintained for a whole-life time.According to the researchers, this all makes sense. â€Å"Knowing that someone is persistent, ambitious and sexy, tells you nothing about how that person really is,† comments researcher Paul Ecstatic. â€Å"It makes no sense finding a partner based on personality traits. â€Å"However, the first impression about one's personality is supposed to be the key point for men in appealing women. It cannot be denied that men's personality is revealed most clearly during flirting stage. Modern women have different tastes of men's charac teristic.According to a survey that study about the ideal kind of men and do romantic things for them. To sum up, women living in today's society are much more different from those who belong to the past. Not only there are differences in position in life but also in human rights especially in choosing a suitable individual for them concerning family, education and personality background. Beside family background, women also care about education background of men. Currently, men are supposed to play the main part in the family economy.In he case of undergraduate guys, girls will want to know about their major, their school and how hard they study. Dating with an intelligent and hard-working guy seems to be more attractive than hanging out with a lazy one. That is all about the ideal man of woman. Next, the research is continued with the remaining gender: male. Researchers have conducted a survey on 1500 men, showed them the survey results and asked them what they think about the stu dy. Surprisingly, the majority of this group agree that woman's too much expectation from her man being idealization is risky.By seeing the list of priorities sought by many modern women, it bevels the truth that many of the modern women seeking their men of their liking are not grown much in mental maturity though happened to have possessed much more educational qualifications. Those men said that woman are too influenced by the media and films, thus, they have an unrealistic expectation of themselves or a potential life partner â€Å"Women these days are more demanding, before expecting much from man, its better to ascertain self first† said M. Chine – one from the survey.Consequently, the survey showed the contrast between men and women about the image of the ideal men. While most of women set for themselves those ideal models, he men do not seem to be in agreement with this point of view â€Å"Women these days are more demanding† – said M. Chine The g raph shows the identification of men about women's requirement. The majority of those men(75%) think that women ‘s expectation today is much higher than in the past. Only a few (6%) agree with this data number. 13 percent of those express a neutral opinion. And the 6 percent left strongly protest against the sentiments.Beside men's option, parents also have their own ideal. Unlike Stationmasters women, Asian women are more like to concern about the parents' approval before starting a relationship of marriage. According to Dry Facet, from Bristol University, he said: ‘Parents want all their daughters to end up with the same level of support, so to achieve this they give more to daughters who have less from their partner. ‘But this leads to conflict over mate choice because daughters can afford to choose an unsupported partner in the knowledge their parents will pick up the slack. He added: ‘The conflict over parental choice. ‘ At the time, it's critical that the daughter stop playing defense. There are reasons that make perfect sense to the parents about why the boyfriend is not the right guy for heir daughter and she's not going to be able to change their minds if she is not look at the same perspective and point of views of the parents. As Asian traditional culture, women must Respect the parents even though they don't approve the relationship. The parents have been around for many years and have more experience in relationship department.Also, the parents can evaluate the pros and cons, most of the daughter in the research, they stated that: â€Å"Parents' disapproval is a sign that you should stop your relationship. † Communicating is also one of the best ways to do when there is no approval. Talking o the parents of both sides to ensure that they all understand the situation and personalities of the boyfriend and even girlfriends so that might conduct a better result and changing the parents' approval through the time a s long as the boyfriend's respect to the parents of the women.Graph Explanation: The pie chart illustrates the opinion of 100 ladies at the age from 18-25 years old on the survey question that â€Å"Is parents' approval affected by the first appearance of daughter's boyfriend? † there is 76% of ladies say yes that the first appearance is important factor for her parents' approval on her relationship; while another 24% says their parents don't care about the first appearance. So what should the daughter do when her parents did not approve for the relationship?Graph Explanation: The graph above was a result of 100 ladies' willingness to do when their parents do not approve for the relationship with their mate. There were 67% of ladies stated that communicating and trying to convincing their parents can help for you relationship get better. Another 20% stated that love is much more important than only one approval; therefore, leaving home with the partner is referred choice whil e there are mom of 43% would keep their relationship regardless the parents' approval. Therefore, parents play an important role in their daughter's choice of mate regarding a serious relationship.In Asian family, daughter still must give the authority to the parents to choose the boyfriend. First appearance of the boyfriend is one of the most important factors that affect the relationship; most parents like the standard appearance for their daughter, which is neat, gentle and knowledge gentleman, to ensure the happy life in the future for their daughter. Ill. CONCLUSION: most suitable with them. All of aspects were mentioned this the former part are the most common standard on which the women based to choose the good men. Therefore, they can be read by men so as to help the men succeed in love.

Ethical issues in organ transplant essays

Ethical issues in organ transplant essays As time progresses and civilization gets more advanced humans continue to develop new ways to increase the quality of life. Unfortunately, the progress of technology magnifies existing ethical problems in medicine. Among the most troubling types of problems for medicine, patients, and society are those concerning the transplantation of human organs. The number of organs available for transplantation are extremely scarce so there are many people who, need an organ transplant, but will never receive one. It is simply not possible to supply a transplant organ to all the people that have a medical need for a transplant. As a result, some propose radically new ideas to meet the demands of organs, some of which include the selling of human organs, and the cloning of humans to cultivate organs. If the justification for donating an organ is charity, then it seems ethically contradictory that one could sell his/her organs. The anatomical integrity of a human body is nearly perfect and should be sacrificed only for the highest of motives, which dose not include financial gains. Moreover, imagine the moral chaos that will ensue if organs were sold to the highest bidder. A person in dire poverty may need the money that would come from an organ donation to support his family. Sadly, society's inability to help him find better ways to support his family may actually force him to sell something that cannot be replaced. While, some argue that since people are paid for their blood, they should be paid for their organs as well, there is a difference between donating blood, which the body replaces, and donating an organ which is not replaced. There is less risk in giving blood and hence their compensation could be justified with a less monetary motive. Even in this regard, I do believe that the nation would be better served if people were not paid for blood donations. Rather than offer an incentive of money, the motivation of helping oth ...

Scorpionflies and Hangingflies, Order Mecoptera

Scorpionflies and Hangingflies, Order Mecoptera The order Mecoptera is a truly ancient group of insects, with a fossil record dating back to the early Permian period. The name Mecoptera derives from the Greek mecos, meaning long, and pteron, meaning wing. Scorpionflies and hangingflies are uncommon, though you can find them if you know where and when to look. Description: The scorpionflies and hangingflies range from small to medium in size (species vary from 3-30mm long). The scorpionfly body is usually slender and cylindrical in shape, with a head that extends into a pronounced beak (or rostrum). Scorpionflies have prominent, round eyes, filiform antennae, and chewing mouthparts. Their legs are long and thin. As you probably guessed from the etymology of the word Mecoptera, scorpionflies do indeed have long wings, relative to their bodies. In this order, the front and hind wings are roughly equal in size, shape, and venation, and all are membranous. Despite their common name, scorpionflies are entirely harmless. The nickname refers to the odd shape of the male genitalia in some species. Their genital segments, located at the end of the abdomen, curve upward like the sting of a scorpion does. Scorpionflies cannot sting, nor are they venomous. Scorpionflies and hangingflies undergo complete metamorphosis, and are some of the most ancient insects known to do so. Scorpionfly eggs actually expand as the embryo develops, which is quite an unusual trait in an egg of any organism. The larvae are most often thought to be saprophagous, though some may be herbivorous. Scorpionfly larvae develop quickly, but have an extended prepupal stage of one month to several months long. They pupate in the soil. Habitat and Distribution: Scorpionflies and hangingflies generally prefer moist, wooded habitats, most often in temperate or subtropical climates. Adult scorpionflies are omnivorous, feeding both on decaying vegetation and dead or dying insects. Worldwide, the order Mecoptera numbers about 600 species, divided among 9 families. Just 85 species inhabit North America. Families in the Order: Note: Only the first five families in the list below are represented by extant North American species. The remaining four families are not found in North America. Panorpidae – common scorpionfliesBittacidae - hangingfliesPanorpodidae – short-faced scorpionfliesMeropeidae - earwigfliesBoreidae – snow scorpionfliesApteropanorpidaeChoristidaeEomeropidaeNannochoristidae Families and Genera of Interest: Just a single species is known from the family Apteropanorpidae. Apteropanorpa tasmanica inhabits mosses in Tasmania, an island state off the mainland of Australia.Hangingflies (family Bittacidae) resemble crane flies, but they are unable to stand upright on surfaces as crane flies can. Instead, the predaceous adults hang from stems or leaves by their front legs, and grab insect prey with their raptorial hind legs.Use a Malaise trap to catch specimens of Merope tuber, the only North American species of earwigfly.Dont handle snow scorpionflies (family Boreidae)! Theyre so well adapted to cold climates, the warmth of your hand can kill them. Sources: Borror and DeLongs Introduction to the Study of Insects, 7th edition, by Norman F. Johnson and Charles A. Triplehorn.Mecoptera, by Dr. John Meyer, North Carolina State University. Accessed December 26, 2012.Family Dinopanorpidae, Bugguide.net. Accessed December 26, 2012.Gordons Mecoptera Page, Gordon Ramel. Accessed December 26, 2012.World Checklist of Extant Mecoptera Species, California Academy of Sciences. Accessed December 26, 2012.

Investigating obstacles and enabling located firms in special economic Essay

Investigating obstacles and enabling located firms in special economic zones - Essay Example The â€Å"special economic zone† (SEZ) is another term used to refer to the formation of modern economic region. In line with this, governments worldwide normally promote the development of SEZs in order to increase the chances wherein the country could experience increase not only in intra-regional and international trade activities but also the inflows of foreign investments and creation of new job opportunities for the local people (Wang, 2013; Brautigam and Xiaoyang, 2011). In the process of improving transportation infrastructure that connects the SEZs to the local market (Baissac, 2011, pp. 24 – 25), ports, and airports, more local and foreign investors will become more attracted in investing in SEZs. Companies that operate in SEZs are normally given special business incentives like duty-free imports, tax holidays, the benefit of having a more simplified procedure when dealing with the customs (FIAS, 2008, p. 2) or reduction in import taxes for foreign-based companies (Gunawardana and Sisombat, 2008). Since each type of SEZ is being governed by a different set of policies and rules particularly when it comes to taxation and conditions on investment and international trading (Dobrogonov and Farole, 2012, p. 5; Baissac, 2011, p. 23), this study aims to focus on analyzing the case of Savan-Seno Special Economic Zone (SASEZ) in Savannakhet Province in Laos. As such, the rationale for zone development will be tackled in details followed by discussing the geographical, economical, and international trade factors that can affect the performance of SASEZ. In relation to geographical, economical, and international trades, this study aims to identify the determinants of FDI, participation strategies used by foreign investors, and the common challenges these firms would normally encounter in SASEZ. The main objective of this study is to identify all geographic, economic, and international trade factors that

In What, After All, Does Happiness Consist for Aristotle Is He Right Essay

In What, After All, Does Happiness Consist for Aristotle Is He Right - Essay Example In other words, moral virtue, however it is attained, will bring happiness. He divides goods into three classes, A person who loves justice, or virtue will find pleasure in carrying out just or virtuous acts. Thus a virtuous person will find happiness in both himself and in acting upon his own goodness, and then be happy. Aristotle further explains that such happiness needs 'external goods' because a person must be equipped with certain other ingredients to perform noble acts. He cites friends, political power and wealth, which can be used to achieve this happiness, and includes certain aspects which might be described as living a 'charmed life' in modern terms. Having noble birth, beauty, good children and so on, all help to enable a person to live well, (think virtuous thoughts, do good acts) and so make a person happy. The inference then is that if someone is ugly, childless, poor or lonely, they have little chance of happiness. be in. However, he does believe that to study and become of good character is the preferred method, leading to noble acts, complete virtue and a complete life. Aristotle acknowledges that changes encountered throughout life might overturn the happiness but concludes that the virtuous activities of man are the most long lasting and permanent, for by thinking virtuously and acting so, he is truly good, and by inference, and in fact, happy. Such a person, described in Chapter 10, will be able to take what life throws at him, handle it because of his 'nobility and greatness of soul' (Bk. 1 Chp. 10, 350BC), always be happy, even in the afterlife. In Chapter 11 he says 'the blessed dead will not be affected by good or bad fortunes of those left behind, their happy state is preserved' (Bk. 1 Chp 11, 350BC). (He considered that what happens to the living impinges on the dead). The hypothesis here would seem to be that thinking good thoughts, doing noble and virtuous acts, staying happy, secure in the knowledge that one is thinking well and living well, makes for happiness, in this life and the next. The soul, being the rational aspect of a human being, will ensure obedience and the production of such virtue will result. His non-evolutionary concept of the universe, (nature is as it is) and how man exists within it, made his ethics fit well with the teachings of the Catholic Church and later, with Christianity as a whole. Serious challenges only arose with the Enlightenment of the 18th Century and the ideas preceding it during the 17th. From Galileo to Darwin, and many others, overturned his views, suffering at the hands of religious leaders in the process. Now, in the 21st Century, surrounded by the knowledge of man's physical, psychological and scientific