Knolege creatain Essay Example | Topics and Well Written Essays - 500 words

Knolege creatain - Essay Example. Balmisse et al (2007 118) take up this concept stating that knowledge management is a shell of tool which , through social interaction and interface customization enables the sharing and transferring of necessary data.In 2010 Martin-Niemi and Greatbanks came up with produced an interesting discussion centering on ba which is tell to be defined as place. This ba becomes the means of relationships being developed, and enabling workers to contribute their knowledge and so enhance their joint experiences and so form a communicative environment which all canister participate and sh are.This figure above shows how knowledge is accumulated when individuals and groups share a common working environment. much(prenominal) sharing is not just the field of a few elite experts, but must include participation by all. An emphasis is made in this type of knowledge creation upon both explicit as well as tacit knowledge as well as how these varying types could b e shared. The former . explicit knowledge, is the easier to share because of its basis in individual talents. The model referred to as SECI, refers to the various stages, i.e. socialization, externalization, combination, and internalization.This model can be used to demonstrate how blogs can be utilised within my company. We became interested in blogs as a way of encouraging groups of employees to contribute the knowledge they had. After only a few months it was possible to see positive developments. However, it was clear that full participation by all employees was necessary in order to create the optimum amount of knowledge. At the present time usage remains limited, but the company is actively developing a programme of incentives with the aim of encouraging employees to share their knowledge.There are a number of benefits to the use of blogs. As well as encouraging the

Facebook.com Research Paper Example | Topics and Well Written Essays - 750 words

Facebook.com - Research Paper ExampleMedia researchers and experts today offer new methods to interact that swallow their basis on the internet as a means of communication. Modern media has readyd a completely new demesne, especially in social relations and has managed to create significant changes in the societal communications. The most young form of human relations has been shepherded by the internet and social networks. Through sharing their private world and minimizing physical distance, Facebook.com and other social networks provide an easier way. Every user is at the same level, apparently, and can experience wide distribute communication in spite of geographic and policy-making borders. The increasing tendency towards Facebook shows that the internet has been greatly affected by it. Considering this, Facebook.com is a pioneer in social networks and is considered as the worlds largest site. With the spread of Facebook, relations are now wider and closer than they have bee n in the past. In fact, Facebook has now become a part of peoples lives, which is inseparable it has some(prenominal)(prenominal) negative and positive effects on a persons life. It is believed by various experts that Facebook has seen relationships enter a new phase where individuals are much aware of one another faster and better. However, on the other hand, other experts believe that Facebook has created many issues. The excessive use of the social networking site, for example, could lead to serious psychological issues that include sever excitement, egotism, anti-social behaviors, and teenage aggression. Facebook users of all ages, it is believed, are more susceptible to getting psychological disorders than those, not on the site (Foregger 26). Based on an resolve by Facebook, there are 200,000 new users each day, which has turned the site into a human network of hundreds of millions (Kord 41). The networking sites increasing popularity has led to some remarkable commercial perspectives for internet profiteers as they each attempt to take control of some piece of the site. This popularity, meanwhile, has been harnessed in pushing social and political programs. Facebook and other similar social networking sites apparently work to form a space for electronic presence of persons, although they are in the service of intelligence and countersign organizations (Kord 41). While Facebook membership is free, nothing is ever free, and in order to use the free electronic services provided by Facebook, people have to put most of their mysteries at these networks disposal (Kord 42). Julian Assange, the founder of whistle blowing site Wiki leaks, claims that the site is probably the most efficient and hateful spying barb that the US government has created to this point. In addition, he contends that that anyone adding their names and their friends characteristics to Facebook needs to be aware that he/she is acting in the interest of spying agencies in the united States, acting to complete their database for them. Facebook, according to Assange, acts as a large database of records and names of various individuals that each user puts at the disposal of the site voluntarily. However, the same hammer is also used by spying agencies in the US, which have access to the information saved by the user on Facebook, which can be taken as a dangerous means against other countries (Kord 43). A number of experts have also pointed out that Facebook harms family integration, creating numerous issues for families and young people (Golbeck 37). One recent example of this is the incidence in which a number of lawyers from the United States announced that 20% of divorces in the country came from Facebook related incidents. Indeed, Facebook

What Is The CAPM (Capital Asset Pricing Model) And Of What Practical Essay - 1

What Is The CAPM (Capital asset Pricing Model) And Of What Practical Use Is It - Essay ExampleWhen the expected return of a security is determined using the homunculus then it can be compared to the estimated return of security over a given time period. Such comparison result help the investor to break up whether it is worthwhile investing into the security. CAPM was first conceptualised and pioneered by William Sharpe, Jack Treynor, Jan Mossin and John Lintner through their independent works (Focardi and Fabozzi, 2004, pp.86-87). The Capital Asset Pricing Model The Capital Asset Pricing Model (CAPM) is popularly used to price individual portfolio securities. The CAPM helps to determine the expected rate of return for an asset relative to market bump. Using the CAPM model an investor can eliminate the un doctrinal risk through proper diversification by estimating the required rate of return for a given level of non-diversifiable or market risk. The practical application of the model is that the individual investor will be able to modify their investment portfolio according to their risk taking behaviour. The model overly helps the individuals to analyse the risk-return profile in the portfolio (Gallagher and Andrew, 2007, pp.173-175). Assumptions of CAPM Investors are risk averse and proportionalitynal No single investor can influence security prices No transaction approach or taxes Investors have access to all information at same time Expectation of the investors is homogeneous Mathematical Formula For individual assets, the relation amongst systematic risk and expected return can be estimated using the Security Market Line (SML). The significance of SML is that it can help the investor to calculate the risk-to-reward ratio for a given security relative to market. (Source Financial Planning Body of Knowledge, 2010) The market risk-reward ratio is also known as the market risk premium. The systematic risk can be estimated using the Beta factor (?). Be ta measures the sensitivity of excess expected return of security to the excess market return. Mathematically, ? = Covariance (Ri, Rm) / variant (Rm) Excess market return or Risk Premium = E (Rm) Rf CAPM = Rf + ? x E (Rm) Rf Where, Rf = Risk-free return Ri = Security lessen Rm = Market Return Market Portfolio and Efficient Frontier The concept of CAPM encourages an investor to invest a portion of his or her wealth in risky asset and the remain portion into risk-free asset. The proportion of asset allocation between risky and risk-free asset depends on the behaviour of the investor. According to this model, a rational investor will prefer maximum return for given risk or minimum risk for given return. The optimum portfolio is a combination of securities which yields maximum returns for lowest risk or volatility. The total portfolio risk can be measured and compared to market risk using beta. The optimum portfolio is derived from the efficient frontier curve that gives the relati on between portfolio risk and return. The combination of securities that is formed at the tangency of individual assets and the capital Allocation line (CAL) is called the optimal portfolio (Khan and Jain, 2007, p.16). (Source krotscheck.net, 2008) The Significance of Beta Factor Beta indicates the linage volatility relative to a benchmark or market. The benchmark can be international index like S&P

Ernest Hemingway Essay Example for Free

Ernest Hemingway EssayThis statement by the writer and journalist, Ernest Hemingway, is not agreeable for me. In my accept understanding of morality, it speaks of a system of behavior in regards to standards of right or wrong. It is not about the tints one can experience after doing something. A feeling is a natural response to our thoughts and intentions. I think not all the decisions that could make us feel good are moral even if it gives us satisfaction and convenience.For example, we all know that abortion or baby butchering is one of the most immoral acts by women today, and even if the mother herself felt the backup and happiness after doing such, it volition remain as an act of immorality in the eyes of God and by the law and humanity. On the other hand, hatful may feel bad of doing something good but they cannot break out from the tracks of morality because of their conscience. In my experience, I often got a negative feeling when Im moving away from my true desires instead of towards them.It means that some people do moral act though it is against their leave alones. Moral decisions are not based solely on the good of a person and a good reason but on making a decision that will not cause harm to anyone. The role of morality is to fair play and harmony between individuals and to keep us in a good kinship with the power that created us. It is not about the feelings but of what you know and what you believe is right and good for everyone.OSD Edinel Magtibay Nov. 27,2008 U2A Chrimora Assignment 3 What is Christian Character of Christian Morality? And how farthest is Christian Morality distinctively Christian and how far it is generally human-that which pertains to common human problems? I give come in order that you might have life life in all its fullness . . . For what my Father wants is that all who see the Son and believe in Him should have eternal life.And I will raise them to life on the last day. John 10 10, 6 40 Life in heaven is t otally different from life on earth. Yet, it is within our capacity to adjust to this pertly life and prepare for it while still in this world. This brings us to Christian Morality, which has to do with preparing to make the quantum leap to new life in heaven eternal life. It has to do with freely choosing to prepare for and participate in the fullness of life that Jesus revealed.

Participants in the study Essay Example for Free

Participants in the take on EssayOf the 40 participants in the study, 26 delivered the maximum shocks while 14 stop before reaching the highest take aims. It is important to note that many of the subjects became extremely agitated, distraught and angry at the experimenter. Yet they preventd to follow orders all the way to the discontinue. So 65% of the participants in Milgrams study delivered the maximum shocks. There were also questions asked regarding the ethics of the study, if we compare it to the British Psychology Societys summary of ethics guidelines (1990) for the conduct of psychological experiments. command trauma Distress to participants must be avoided but does not stick outm to be the case in this research with participants concerned they are harming the learner. Informed react this must be gained with an explanation of the research where ever possible. In this study to the give the participant a full explanation would not have got had the results that the y got in the first spotlight. They would have caused questions regarding the validity of the research. This then leads us to- double-dealing They were not fully aware of what was going on or the aims and objectives of the research so at that placefore they were deceived.Debriefing Milgram fully debriefed the participants and did this extensively and out of all of the participants that 84% were glad to have participated, while only 1% regretted their involvement. The right to withdraw the participant does have this right but this was not really the case here as here when a participant wanted to stop the experiment, the experimenter probed the subject to continue, pressure was added to continue the study so as not to affect the data. Protection of Participants now this is from both physical and psychological harm which was not the case in each component.This study would not be able to be completed today due to the ethical issues affecting this but as you saw in the results th at it did excavate that people would obey even after they believe its wrong. Now if we look at Zimbardos (1971) in his study The Stanford Prison Experiment he was looking to see people conforming to complaisant roles according to what people believe about a given situation. So for example this was how the prisoners would obey the guards orders if they believed that they were in jail. The reason that this appealed to Zimbardo was he was a former class mate of Milgram and was interested in expanding on his research.Zimbardo set the experiment by first placing an advert in the paper enquire for male students to participant in a prison life experiment. The students who applied there were 24 in total they were selected from larger group that had applied for the study because they had no psychological issues, medical condition and no criminal backgrounds. They were all agreed to be in for one to two weeks for the experiment. The experiment was due to pull round two weeks but this had to be stopped early due to what was happening to the participants.The guards became abusive and prisoners began to show signs of extreme anxiety and stress. Neither the prisoners nor the guards were advised on how to move with the each other. The guards began to behave like real life guards but they were also aggressive towards the prisoners, and the prisoners became passive and depressed. Five of the prisoners began to experience such severe negative emotions, that they had to be released from the study early. According to Zimbardo and his colleagues, experiment shows the powerful role that a situation can play in human behaviour.Because the guards were placed in a bureau of power, they began to behave in ways they would not normally in their everyday lives or in other situations. The prisoners, placed in a situation where they had no real control, became passive and depressed. The experiment could like Milgrams could not be repeated by researchers today because it fails to meet the standards established by numerous ethical codes which I am going to look at now, by comparing the experiment to the British Psychology Societys summary of ethics guidelines (1990) for the conduct of psychological experiments.General Distress this was caused to both the prisoners and the guards, as the prisoners were humiliated and the guards became more and more aggressive which was caused by them wanting to do what they were supposed to do. Informed Consent This was again something that they were unable to do as this may have had an effect on the results of the experiment, the participants were aware of certain things like that they were part of a prison experiment but not the aims and objectives of the experiment.Deception due to the fact they the participants were not fully aware of what was going on and what was expected or wanted means there is a certain level of deception in the experiment. Debriefing Zimbardo did debrief all of the participants but there has been sugg estions that this was not enough or a through with(predicate) as Milgrams debriefing process. discipline To Withdraw Like during the Milgram experiment the participants did have the right to withdraw but when they asked or showed that they wanted to blank out they were persuaded to stay.Eventually a few of the participants had to be allowed to leave early as they were beginning to show extreme stress. Protection of Participants this was the biggest area that was had ethics question raised, the participants were under a lot of stress, they began to believe the things that were being express to them and how they were being spoken to, they began to lose their identity which again caused stress, many of the participants became emotional under this pressure and some even became aggressive. The guards were inflicting this on them but this was situational.The experiment came to an end early when another psychologist realised on how far this had gone. Even Zimbardo himself said that h e began to believe that he was the prison warden not the lead psychologist. Despite the critique that this study received it is still important in psychology and how a situation can influence behaviour. The study more recently was brought to light when there were questions being asked of soldiers treatment of prisoners in Abu Ghraib, and many people and even Zimbardo himself suggested that this may have been the real world example of what he was trying to achieve through research.To conclude there are many things that influence behaviour in people, wither that be their own beliefs and opinions or other people being round them at the time, they way in which people work is very complex and the study although brilliant at the times with the break through that they made into the social side of psychology have raised questions over the ethical issues that are also something to be looked at.Today the studies would not have been able to take place and in some ways this is a shame as we w ould not may be have had the knowledge that we have now because of them. Yet if they had horizon of other ways around to come up with the same type of results then this would have been better for all of the subjects concerned. I think the research that was make was invaluable and that psychologists will always believe this just the questions over the methods leave a small black cloud over something rather brilliant.ReferencesBooks Cardwell, Clark, Meldrum, Wadeley. Psychology A2 for AQA (Fourth Edition) HarperColins. Gross, Richard Psychology, the comprehension of Mind and Behaviour -Hodder and Stoughton Gross, Richard. , McIlveen, Rob. , Coolican, Hugh. , Clamp, Alan Russell, Julia. Psychology a new introduction for A2 Hodder and Stoughton. Websiteshttp//wilderdom.com

Education and the Brain Essay Example for Free

Education and the Brain EssayGiven the emerging challenges surrounding the practice of education, many a(prenominal) scholars and researchers are trying to establish a particular framework that is dedicated towards the enhancement of information and intensifying facilitation. With these processes, at that place is one important and vital determinant of this situation the mans headland. In the advent of new capabilities, focus is now related on discovering and creating opportunities that seeks to enhance the relationship between the brain and education.The article of Bruer offers a comprehensive insight close to the strength and weaknesses of such(prenominal) field. Tracing from the past, he emphasized how the discipline has evolved from a mere scientific study to reaching out in the realm of nestling development and education. As individuals and groups try to unearth the processes involve, it branched out to several unique disciplines that correlate with the concept of ed ucation namely cognitive psychology and neuroscience (Bruer, p. 3). run on this scheme, there are two ways in which this can be recognized namely (1) the period of synaptic elimination and (2) critical periods (Bruer, p. 3). In the first part, Bruer points out the relevance and relative link between neuroscience and education. In this process, he mentions that there are various brain activities that are stimulated by synapses that affect the way a claw can cope with numerous functions that are expected for him/her to perform in a classroom setup (Bruer, p. 4).At the same(p) time, the document made mention the importance of the experiment concerning critical periods. With numerous ways for this case to be applied, researchers have focused on the thinking that these actions are vital in the early advancement of an individual. Bruer argues that cultural variations in child rearing suggest that there are many equally sure-fire way to provide the normal environment needed for brain de velopment (p. 5). The next section caters in looking into environments that are vital for a childs advancement during the early stages of his/her life.It fosters the claim that stimulating and active surrounding does contribute to the overall capability of an individual to function accordingly with the desired objectives and name and addresss of an institution. However, there is a lapse in neuroscience as it fails to include and elaborate on how such process can be vital in the overall goal of education and growth (Bruer, p. 7). This remains to be the missing link in trying to determine that guidance of the brain functions in classroom instruction and teaching.On the other hand, Bruer cites the capability of creating a bridge that will enable the brain to relate its functions towards cognitive functions. In this process, there are two ways that such idea can be recognized. Bruer mentions that the first connects educational practice with cognitive psychology, and the second connect s cognitive psychology with brain science (p. 7). In here he cites numerous advancements in technology and equipments available nowadays to help study and examine the progression of mental activity happening in an individual.Similarly, using the mind-brain interface, many researchers and scientists are able to conduct tests that can determine which part/areas are vital in particular function that are used and applied in the educational sector (Bruer, p. 8). In the last part, it seeks to elaborate these bridges by pointing out two viable approaches in dealing with it namely (1) instruction to light and (2) cognition to neural activity. The first part looks into the way cognition has been used by educators and scientists to determine appropriate ways to enhance neural activities.At the same time, it focused on several studies and findings that try to relate these instances. In the second part, Bruer points out the use of cognitive models and brain recording techniques to trace the ne ural circuitry involved in a skill like numerical comparison (Bruer, p. 10). It is in here that they were able to find the connection between the two. In the end, the article argues that the brain can greatly affect the way individuals respond to the education. Therefore, future studies must guide researchers in addressing the loopholes in the current literatures.As the demands for educational policy continues to add-on significantly in the practice, a good basis for such study can be made by relating to one important factor that shapes learning and development the brain. It is in here that we can find appropriate strategies to increase competency and skill acquisition needed to make students dynamic and vibrant in practice.Work CitedBruer, John T. Education and the Brain A Bridge too Far in Educational Researcher 26 no. 8 1997. accessed 12 November 2008. 4-16.

SUPA Accelerators Overview and Applications

SUPA Accelerators Overview and ApplicationsAimee HopperNovember 28, 20131 Briefly describe the differences in the midst of the fol first gearing ac-celerators and get around their advantages and disadvantages(54 Marks)Accelerates Protons/Ions with a Kinetic Energy of 20-35 MeV.The per reboundance d iodine on the touch is proportional to the potential drop of the terminal. (W =qVterminal). The voltage of the terminal is dependent on the height of the device (V _ kQL )where Q is the total institutionalize of the members, k is the deoxycytidine monophosphate constant and L is the total length of the accelerating chamber, i.e. the total height of the device through which theion falls.Advantages real simple to confuse, and the principles behind the acceleration atomic number 18 really headspring understood.easy and cheap to maintainDisadvantagesvery difficult to get to very game energies, as the only way to do so it so make a very high, st equal structure.only allows one rou te for fractions to travel.Betraton (6 Marks)Accelerates electrons with a energizing thrust of 10-300 MeVThe betatron is a type of accelerator which uses an induced magnetized field to accelerate electrons to high energies in circular orbits. Uses solenoids with an electric current passing through to produce large magnetic field to bend the particles.Advantages sincere design solenoids and their properties are well understood and dirty dog easily be tested and manufactured.DisadvantagesRequires a huge amount of coils to get the induced magnetic fields require on that pointfore very heavy and costly.As the coils arent superconducting, this system is as well as very lossy, and so wastes a lot of qualification.Cyclotron (6 Marks)Figure 2 3Accelerates Protons/Ions with a kinetic energy of 10 100 MeV.A circular device which operates using large magnets to bend the particles. Two semi-circular plates are connected to an AC source, applying a voltage across a gap between the pla tes. This applied voltage causes the particle to accelerate. However, as there is also a large magnetic field present, the particle is oblige to bend its path as it accelerates, following a circular path. The more energy the particle gets, the larger its radius becomes until eventually it is extracted from the device. (v = qBr m where q is the charge of the particle, B is the magnetic field strength applied across the plates, r is the radius of curvature of the particle and m is the mass of the particle.)AdvantagesThe akin gap quarter be used for all energies of particles, as the kick that is received leave always be in-phase with the kick produced by the AC source. This is because as the particles speed up, they provoke a longer path, therefore take longer to arrive to the same point they were originally.DisadvantagesTo have a small device, large magnetic fields are required, which could pose a hassle to the set-up and cost of the project.As the particles become relativistic, the AC source lags behind, therefore not producing the correct kick to the particles, possibly removing energy from the system.Synchro-cyclotron (6 Marks)Accelerates Protons/Ions with a kinetic energy of 100-750 MeVSpecial form of cyclotron takes into account relativistic lag from the AC sources.AdvantagesThere is no need for a narrow gap between the plates as in the case of conventional cyclotron, because strong electric fields for producing large acceleration are not required.So, only one plate is required instead of two, the early(a) end of the oscillating voltage supply being connected to earth.The magnetic pole pieces can be brought closer, thus making it accomplishable to increase greatly the magnetic flux parsimoniousness.The frequency valve oscillator is able to function with much greater efficiency.DisadvantagesThe machine produces high energy ions with a comparatively low intensity.Synchrotron (6 Marks)Figure 3 ?Accelerates either electrons (kinetic energy of 1-10 GeV) or protons/ions (kinetic energy of 1-1000 GeV).Utilises a number of different types of magnets dipoles (bend the beam), quadrupole (focus the beam), sextupoles (account for chromaticity of the beam) etc.Uses RF cavities to insert energy into the particle beam to account for synchrotron losses and increase the energy of the beamAdvantagesCan generate a high luminosity beam at very high energies.The Synchrotron radiation lost can be used for other applications which require a very specific swanlength, such as medical applications.DisadvantagesSuffers from radiation lossesA synchrotron cannot use relativistic particles, as RF lag would become an issue.Storage ring (6 Marks)Accelerates electrons with a kinetic energy of 1-7 GeV European Synchrotron Radiation Facility.A storehouse ring is a particle accelerator that keeps a particle beam at a certain energy for a long period of time. This is useful, peculiarly in synchrotrons, as the beam can be kept at a certain energy ensuring th at a specific frequency is emitted in the form of radiation.AdvantagesStores a particle beam at a certain energy, so dont have to increase beam energy from 0 (time consuming).DisadvantagesSystems have to be very precise and stable costlyCollider ring (6 Marks)Accelerates electrons (kinetic energy of 10-100 GeV) or protons/ions (kinetic energy of 1-7TeV Large Hadron Collider).Particles of a particular energy are injected into the ring and stored there until they are forced to collide at set points throughout the structure.AdvantagesCan r separately higher energies than in a LINAC at much lower cost ascribable to giving each beam half the required centre of mass energy.if using particle-antiparticle, then the same equipment will accelerate the two beams in other directions (due to difference in charge)DisadvantagesBeam pipe needs to hold 2 beams, which need to only interact with each other when required need very accurate equipment to ensure beam stays separated.Linacs (6 Marks)Ac celerates electrons (kinetic energy of 20 MeV to 50 GeV) or protons/ions (kinetic energy of 50-800 MeV Los Alamos Meson Physics Facility)A Linear Accelerator accelerates the particle beam along a straight line as irrelevant to a circular path.AdvantagesNo energy loss due to particles accelerating in a curve.Can accelerate heavy ions to far higher energies than possible in the circular accelerators.Can produce a continuous stream of particles as opposed to thumpinged particles present in circular accelerators.DisadvantagesNeed to be very long to get up to high energies.A high number of AC driver sources are required, which is both costly and introduces possible errors due to out-of-phase issues.Linear collider (6 Marks)Accelerates electrons from 50-1000 GeV.A linear collider is used to collide particles in a straight line towards one another.AdvantagesNo energy needs to be pumped into the beam to account for radiation losses.beams will never be able to interact with each other bef ore the smash points, therefore can use smaller beam pipes.can accelerates heavier particles since they dont need to be bent.DisadvantagesFor collisions with the highest possible energy, two linacs producing beams with the same energy headed towards each other, the complete machine would need to be very long2 Explain the advantages of using a collider rather thana single beam for collision experiments. Illustrate youranswer by considering 7 TeV proton beams. (10 Marks)By using 7 TeV proton beams in a collider, a centre of mass energy of 14 TeV can be achieved by sending both beams in opposite directions to collide. This is obviously very useful when probing matter, as a higher energy will result in higher mass particles / more low mass particles being produced, therefore available for analysis. The single beam would only be able to reach 7 TeV, and so has a limited range by comparison to the collider.To obtain a centre of mass energy of 14 TeV in a single beam is also incredibly di fficult to produce, both due to the cost and the size of the equipment required. Therefore a 14 GeV beam isnt operable to produce. Whereas 7 TeV is relatively easy. Also, when 14 GeV does become easy to produce, a centre of mass energy of 28 GeV would then be possible, which is far more harming for high energy energy studies.3 Explain briefly how a laser-plasma wakefield acceleratorworks. What determines the limit in energy for a uniformplasma density? (13 Marks)In laser-plasma wakefield acceleration, a laser pulse is used to excited very high electric fields in a following plasma wave. effectual energy transfer is made between laser pulse and plasma wave if both the wave and the pulse are travelling at the same speed, with a high energy gain being obtainable in low-density plasmas, in which the phase amphetamine of the laser-plasma is equal to the laser pulse group velocity, which is very close to the speed of light. This allows the longitudinal electric fields associated to t he fast plasma wave to accelerate relativistic particles within the plasma, and can even muddle the particles to the electrostatic wave. This allows particles to be boosted to very high energies in a very short distance.It is important that the density of the plasma is below the critical density (nc =11 _ 1021=_20_m)5We know that the maximum energy of a wave is related to the 2g of the wave by the equationE _ epn _1g (1)where g is the lorentz factor associated with the group velocity of the laser pulsewhich is equal tog =0p (2)So the more dense the plasma, the lower g is, and therefore the slower the wave travels. If the wave travels too slowly, then the particles will move away from the wave faster.4 Briefly describe how a FEL and synchrotron radiationsource works. What is the advantage of a free-electronlaser? (10 Marks)A free-electron laser utilises both undulator and radiation fields to produce ponderomotive (essentially a light-radiation pressure) on the particles. This forces the electrons to oscillate at the fundamental frequency. If the electrons can be forced to bunch together on a wavelength scale (given by equation 3), then the electrons emit coherently._ =_u22_1 +a2u2_ (3)Synchrotron radiation works by accelerating a particle in a circular path, therefore producing radiation. This generally gives an incoherent beam of radiation, as any discrepancies in the individual particle energies will result in a meagrely different frequency radiation coming o_. It is caused by undulators, wigglers and bending magnets, and due to the high speeds of the particles, comes out the acceleration device in a cone, with an opening cant over equal to _1 .The benefits of the free-electron laser are that it produces a much higher brightness due to the coherence of the wave, therefore producing a significantly higher photon flux for a given energy, as compared to the synchrotron.Synchrotrons currently produce an average brilliance of 1011. The FEL is able to produce a brilliance of up to 6 orders of magnitude higher, however there are currently issues with regards creating coherence throughout the whole length of the laser pulse.5 Describe how particles and X-rays can be used to treatcancer and give the advantages and disadvantages of thedifferent radiation types used for radiotherapy. (13 Marks)With regards to cancer, the aim is to footing or destroy the DNA of the tumour to kill it by disrupting the cell cycle of the tumour in one way or another.X-Rays produced in 5-20 MeV linacs are currently used to treat most patients. They can cure up to 45% of cancers, 50% of which is by radiation therapy alone, or combined with chemotherapy and/or surgery.This is achieved by using 3D Conformation therapy, where multiple X-Rays are used to concentrate the beam energy onto the tumour, whilst minimising the damage caused to surrounding cells.Particles that can be used to treat cancers include electrons (positrons), protons, neutrons and ions. These can eith er be used directly, or can help in producing radio-isotopes to also assist in treating cancer through Positron Emission Tomograohy (PET) or Single Photon Emission Computed Tomography (SPECT).If used directly, then the particles are _red at the tumour. aerated particles interact with electrons in the body, and a vast majority of the energy of the particle is deposited according to its Bragg Peak (energy loss vs distance plot of the Bethe-Bloch formula).The aim is to get this erudition to correspond to that of the tumour, so the energy deposited causes maximal damage to the cancer whilst causing very little damage to surrounding tissue.The advantages of particle therapy areAll (most) energy deposited where required, with little to no damage of surrounding cells.Very few side effectsSeems to have a higher cure rate with certain types of cancers (i.e. uveal melanoma).Massively reduces the damage done to children sufferers as less of their healthy tissue is effected, reducing the chanc es of side-effects caused by traditional methods.Particles can be accelerated to whatever energy is required to reach the tumour.The disadvantages of particle therapy areIt requires a huge capital investment, and is massively expensive by comparison to X-Ray treatments.Requires hospitals to have room for a large particle accelerator to accelerate the ions, which isnt always possible.Expensive to run, due to energies required.References1 http//www.lbl.gov/abc/wallchart/chapters/11/2.htmlas viewed on the 25/11/132 http//commons.wikimedia.org/wiki/ registerWideroe linac en.svgas viewed on the 25/11/133 http//images.yourdictionary.com/cyclotronas viewed on the 25/11/134 http//www.schoolphysics.co.uk/age16-19/Nuclear physics/Accelerators/text/Synchrotron /index.htmlas viewed on the 25/11/135 V. Malka, J. Faure, Y. Glinec, A. Lifschitz, LASER-PLASMA WAKEFIELD AC-CELERATION CONCEPTS, TESTS AND PREMISES, EPAC, 2006