Electrical Properties Quantum Transport in Nanowire Device

Electrical Properties Quantum Transport in Nanowire Device David S. Murdoch Nanowires are quasi one-dimensional rod-like nanostructures with diameters in the order of nanometres (10^-9m) and have seemingly unlimited length and a great degree of versatility. Nanowires form as monocrystals in a well defined crystal geometric direction. Nanowire geometry allows for easy contacting of the wires from two sides. Attention is devoted to geometry of nanowires because this is the feature that allows for easy control of electronic properties of nanowires.[1] Growth orientation (e.g. 100), the faceting arrangement (e.g. [100]) and the surface structure (Si(100)) are generally outlined in nanowire investigations and are a generally accepted notation to depict nanowires. A nanowire is thin and diameter is in order of magnitude far smaller than length of nanowire. As diameters gets larger, quantum effects become less significant against bulk material properties. Nanowires have thermoelectric properties, specifically that they have high thermal stability and low thermal conductivity. Quasi one dimensional Carbon Nanotubes (CNTs) and nanowires are likely composite materials for future electronic devices.[1] Nanowires electrical properties are easier to control than CNTS, therefore are an attractive alternative to CNTs and naturally passivated when semiconducting.[1] Under scrutiny, experimentally grown nanowires always have passivated facets but further study of unpassivated (pristine) nanowires has demonstrate fundamental mechanisms at an atomic-scale. One of which being that passivation is necessary to obtain nanowires with those controllable electrical properties.[1] Semiconductor nanowires can form from materials such as: Silicon, Si Indium Arsenide, InAs Germanium, Ge Indium Phosphide, InP Gallium Nitride, GaN Zinc Oxide, ZnO Cadmium Sulphide, CdS Nanowires can also be made from metallic materials and oxidised to make insulators but semiconducting crystalline nanowires are ultimately more useful in devices. At the atomic-scale, although impurities are useful sometimes, small variations can cause serious unwanted alterations to electronic structure. [1] Semiconducting nanowires are often fabricated via growth mechanisms or synthesised by electrochemical etching. These processes are often done in an aqueous solution with HF acid. The most common method of nanowire growth is Vapour-Liquid-Solid (VLS) mechanism. VLS is a bottom-up process that starts with the dissolution of gaseous semiconducting materials with colloids of a metal catalyst, generally gold or silver [2]. The one-dimensional growth is evoked and dictated by the colloids. Once the colloids are supersaturated with semiconducting material, crystalline nanowire growth will start to occur at a boundary between solid substrate and liquidised material. This particular description was the growth of silicon nanowires. One example of EE is the use Ag catalyst on wafer-scale Si to fabricate a nanowire array. Ag+ ions are reduced in the solution after holes are inserted into the valence band of Si substrate. The reduced Ag nanoparticles dictate the extent of the etching and oxidation processes. Vertically aligned nanowires result from this synthesis.[3] After both methods of fabrication, nanowires remained anchored to substrates and are similarly dependent upon length of diameter for thermoelectric properties. However, wires from EE have much rougher surfaces than that of VLS. [Si nanowires yielded from EE have much rougher surfaces than typical Si nanowires grown via VLS and have less thermal conductance.[3] A heterostructures are the junctions between two different crystalline semiconductor materials essentially two different nanowire materials formed together to make one nanowire with unique properties. Heterostructures are commonly grown via VLS.[2] These heterostructures allow nanowires to have multitude of properties. What is a semiconductor and how does it work. By strict definition, a semiconductor has a conductivity between 105 and 10-5ÃŽ ©-1m-1. This is in contrast with insulators that have conductivity of approximately 10-24ÃŽ ©-1m-1 and metals that typically have 107 to 108ÃŽ ©-1m-1. On the face of them, these numerical values are rather meaningless but they do show that a semiconductor is separate from the other two, a true genuine third category of material.[4] How a semiconductor conducts is best described by a conduction and valence band. The conduction band rests above the valence band. The conduction band contains excited electrons and the valence band contains holes. In an insulator the two bands are a vast distance away from each other. In a semiconductor the two bands are much closer together, almost touching. If a bandgap is small enough, thermal vibrations may provide enough energy for some electrons to excite from the valence band to the conduction band. In a metal the two bands overlap, leading to a low resistivity in metals.[4] The diagram below depicts what the above description. An intrinsic semiconductor has a completely filled valence band, electron and hole populations are always equal. [4] An extrinsic semiconductor is doped. Midway between the two bands lies the Fermi energy. Below the Fermi energy. At absolute zero, no electrons we be able to excite past the Fermi energy.[12] In n-type and p-type semiconductors, the Fermi energy is adjusted to be closer to valence or conduction band.[12] Between the two bandgaps there is a sea of electron density. A transistor is a semiconducting electronic switch and are commonly found embedded in integrated circuits. Down-scaling of the gate length over the years has technological devices reduce in size has caused field-effect devices to having significantly less electrostatic control of a path of conductance; more capable device have been developed such as FINFETs, Trigate transistors and ultimately gate-all-around devices (GAA).[4] Nanowire devices can come in all shapes, not sizes. Examples of nanowire devices are Field-Effect Transistors (FETS), LEDs, Tunnelling diodes, Elementary logic gates, lasers and biochemical sensors.[4] There are a number of different FETs but Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) might be the most interesting or relevant in near-future technologies and are examples of GAAs. MOSFETs are extrinsic semiconductors where the doped material has been oxidised for some insulating properties. If a metallic gate anode were deposited you have the foundation of an electrical switch. [crystalline] Carrier charge density can be changed at the Fermi energy. If the semiconductor were p-type (i.e. abundance of holes in valence band) and a positive voltage is applied to the circuit then the electrostatic energy of the holes increases. Although holes are pushed away from the anode, any attracted electrons do not compensate for the decrease in positive charge. The switching effect is reduced if charge can be stored at the interface between the insulating barrier and the Si since the potential of the silicon will be less than that of the applied gate.[4] When voltage is increased beyond a certain point electron concentration at the surface of the Si will exceed the hole concentration. This creates the on/off switching effect. This gate voltage is large enough so that the bottom of the valence band moves down. The switching effect does not work with a metallic material because the valence band would be too high still and a Fermi energy could still carry current. The semiconductor band gap controls on/off electron currents.[4] Are nanowire MOSFETs superior? Smaller semiconductor gates allows speeds up operation from shorter distances, lower areas of capacitances and Larger fields but it is risky to store charge in a transistor so small and new quantum effects come into play at a nanowire-scale. One of the capabilities of these new technologies is to produce potentials which can confine electrons to the same scale as their Fermi wavelength. Nanowire MOSFETs can also be used in high frequency circuits. In Electron microscopy high energy electrons are fired at an object and reflected electrons are collected and computed into an image. Electron microscopy generally has greater magnifying power than optical microscopes. There are two main electron microscopes and they are Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). SEM uses secondary electron to help generate an image that gives the viewer an impression of 3D while TEM fires at thinner objects at produces a 2D image but while ultimately be more useful for imaging nanowires.[7] Larger batteries potential differences require more conductive metals. In recent years Lithium has grown popular as a cathode. Semiconducting Si could be an attractive anode for Li cathode batteries as both metals become more ubiquitous. Although Si has low discharge potential and charge capacity 10x higher than existing graphite anodes and even more so than oxide and nitride materials, Si anodes in bulk form have limited use because silicons volume is drastically altered during extraction and insertion of Li. Resulting in capacity fading and pulverisation after recharging cycles. This is depicted in the diagram below. [8] Anodes made of Si films have a stable capacity over many cycles but are not viable as a battery because they waste away over time. Nanowire are a superior alternative to bulk materials because of a piezoelectric effect: â€Å"Crystals which acquire a charge when compressed, twisted or distorted are said to be piezoelectric. This provides a convenient transducer effect between electrical and mechanical oscillations.†[9] Each Si nanowire is grown and electrically connected to a metallic substrate surface thus all nanowires contribute to the battery capacity. During Fossil fuel combustion 15 TW of heat is lost to the environment. Thermoelectric modules could potentially convert part of the heat waste to electricity.[3] As of 2008, Bi2Te3 in its bulk form was the most commonly used material for thermoelectric devices. However, it is difficult to scale bulk Bi2Te3 to large-scale energy conversion in power plants but fabricating synthetic nanostructures of Bi2Te3 for this purpose is even more difficult and expensive. Thus, Bi2Te3 is replaced with increasingly ubiquitous Si.[3] Ubiquitous Si, abundance with a low-cost and high-yield products thanks to economies of scale. Si also has advantages in thermoelectric applications. Critical spacings below 300nm in Si would reduce thermal conductivity since Si has larger differences in mean free path lengths between phonons (~300nm) and electrons (110nm) at room temperature.[3] InAs-based semiconductor nanowires can already provide a convenient basis for the development of more complex hybrid nanostructures and can contact Schottky barrier-free with metals.[6]The InAs superconducting nanowires are fabricated via catalytic process based on the VLS mechanism.[6] InAs nanowires can be grown epitaxially. Epitaxial growth means the deposited material continues to grow on the same crystalline lattice as its substrate.[2] A superconductor is material with with no resistance and generally operates at a lower temperature. Within semiconductors, there are electron pairs, separated by vast distance in comparison to the lattice spacing, are coupled. These so-called Cooper pairs can exhibit boson characteristics and condense to a ground state since their attraction produces a small pair binding energy similar to the Fermi energy level.[10] A supercurrent generates no waste heat or any other form of waste. The supercurrent can be switched on or off by the electron density acting like a transistor as described earlier. Nanowires acquire superconducting properties because of the proximity effect, a phenomenon that can occur as Cooper pairs of electrons from a superconductor flow into a normal conductor at a junction. Nanowires arent inherently superconducting or easy to make superconducting.[6] The proximity effect manifests itself through the appearance of a supercurrent, which can be viewed as a consequence of the diffusion of Cooper pairs throughout the entire length of the nanowire section between the two superconducting electrodes.[6] the proximity affect can only happen if the boundary between Superconductor and semiconductor allows electrons to move freely. Cooper pair tunnelling is an explanation of Cooper pairs where they are able to interact through quantum tunnelling. At a junction between two superconductors a nd a more resistive material i.e. S-N-S junction. Two Cooper pairs across from each other in two separate semiconductors, can feel an attraction and readily flow into the normal conductor dividing them. S-N-S junctions will also feel a Josephson effect. Cooper pair could be created in the superconductor electrons in the Fermi energy being reflected at the S-N boundary.[6] This could be because of tunnelling effects. But what of Tunable supercurrent? How can a hybrid superconductor-semiconductor device work to observe quantum phenomena? Josephson behaviour occurs at critical currents. The nanowires allows the critical current to be controlled by voltage at a gate, Vg. If this voltage is negative then electron density is reduced and nanowires perform as the weak links between tunable superconductors.[6] With the use of certain geometries, there is the possibility of controlling individual nanowires on the same IC. Majorana fermions are particles that are their own antiparticle.[13] Not much is still known about Majorama pairs, not all the theory has been made to explain them and their properties yet. They are also examples of non-Abelian anyons.[14] In the vicinity of a Zeeman field, semiconducting nanowires require strong spin-orbit to induce majorana pairing in between electron states. This proximity effect induces a topological superconductor. Majoranas can be detected by Tunnelling Spectroscopy. A superpostion of Majorana particles states will always be zero energy because the particle and antiparticle have opposite energy.[14] Said zero energy state can be found in a normal conductor acting as a junction.[11] How to summarise this dissertation? The task received was to research and review electrical properties and quantum transport in nanowire devices. This task down into an explanation of base nanowires, specifically semiconducting nanowires. Then, general devices such as transistors, batteries and thermoelectrics were reported on and how certain applications have taken advantage of nanowires in respective devices. Then analyse of quantum effects in Cooper Pairs in superconductors and Majorama fermions. Technology is advancing at an exponential pace. The smaller components can be the more attractive they to companies who manufacture and sell consumer products. The smaller a transistor is the more you can fit on an integrated circuit leading to smaller more powerful products. Majorama fermions and Cooper pair tunnelling probably wont be used in any consumer applications in the near future but nanowire semiconductors in junctions placed between superconductors show means of electrically me asuring quantum tunnelling. In the near future investigations of these particles will enhance fabrication and measuring techniques and eventually manipulate and control Majorana qubits. They are examples of non-Abelian anyons[14], quantum state after partilce exchange making them ideal for use in topological quantum computing.[13] References R. Rurali, â€Å" Structural, electronic, and transport properties of silicon nanowires†, Reviews Of Modern Physics, 82 427-449 (2010) Law, M., Goldberger, J., Yang, P. D., â€Å"Semiconductor Nanowires and Nanotubes†, Annual Review of Materials Research, 34, 83-122 (2004) Hochbaum, R. Chen, R. D. Delgado, W. Liang, E. C. Garnett, M. Najarian, A. Majumdar, P. Yang, â€Å"Enhanced thermoelectric performance of rough silicon nanowires†, Nature 451, 163-167 (2008) Crystalline Solids lecture notes http://cxs.phys.soton.ac.uk/mwf/mediawiki-1.21.2/images/7/70/2013_lecture_notes.pdf Egard M, Johansson S, Johansson AC, Persson KM, Dey AW, Borg BM, Thelander C, Wernersson LE, Lind E, â€Å"Vertical InAs nanowire wrap gate transistors with f(t) > 7 GHz and f(max) > 20 GHz†, Nano Lett. 10, 809-812 (2010). Y.-J. Doh, J. A. van Dam, A. L. Roest, E. P. A. M. Bakkers, L. P. Kouwenhoven, S. De Franceschi, â€Å"Tunable Supercurrent Through Semiconductor Nanowires†, Science 309, 272-275 (2005) C. T. K.-H. Stadtlà ¤nder, â€Å"Scanning Electron Microscopy and Transmission Electron Microscopy of Mollicutes: Challenges and Opportunities† Modern Research and Educational Topics in Microscopy, 123 (2007) C. K. Chan, H. Peng, G. Liu, K. McIlwrath, X. F. Zhang, R. A. Huggins, Y. Cui, â€Å"High-performance lithium battery anodes using silicon nanowires†, Nature Nanotech. 3, 31 35 (2008) Piezoelectric Effect, HyperPhysics http://hyperphysics.phy-astr.gsu.edu/hbase/solids/piezo.html Cooper Pairs, Hyperphysics http://hyperphysics.phy-astr.gsu.edu/Hbase/solids/coop.html V. Mourik, K. Zuo, S. M. Frolov, S. R. Plissard, E. P. A. M. Bakkers, L. P. Kouwenhoven, â€Å"Signatures of Majorana Fermions in Hybrid Superconductor-Semiconductor Nanowire Devices†, Science 336, 1003-1007 (2012). Fermi Level, Hyperphysics http://hyperphysics.phy-astr.gsu.edu/hbase/solids/fermi.html Leijnse, M., Karsten,F., â€Å"Introduction to topological superconductivity and Majorana fermions† Topical review 1-20 (2012) http://arxiv.org/pdf/1206.1736v2.pdf Enter the Majorana Fermion, Sciencemag.org, http://www.sciencemag.org/content/336/6084/989.full.pdf

Nursing Reflective Essay on Ethics Committee

Nursing Reflective Essay on Ethics Committee LOVISE GEORGE EXPERIENCE IN THE VIRTUAL ETHICS COMMITTEES Reflective Critique Method As a part of our course, we should engage with six ethics committee. I have attended six ethics committee which has profoundly changed my experience in Teesside University. This reflective essay will use Gibbs reflective cycle (1988) and explain some of my experience in the ethics committee and how I managed in certain situation. I am concentrating on particular aspect participant information sheet. The incident occurred during my first ethics committee which I was due to delivery about my topic participant information sheet. I felt so miserable during at the time, this was my first experience to attend in this session so I have no much knowledge about research topics and terminologies .I thought that participant information sheet means it includes only the participant information and we should write about all details about participant details. My task was to speak about participant information sheet, looking at how this important for researcher what are the criteria should be included in information sheet .When I started to speak about my topic I become so tensed and I am not able to convey my ideas to other members. I stumbled with my first sentence so I could not able to complete my presentation .I felt shy and ashamed about my ability to speak to other members, but I felt so sad towards me and trying not to cry. When the class was finished immediately I left the class room a nd did not speak to anyone. I realized that have no confidence to speak in front of my colleagues and tutors about my subject. Totally I attended six ethics committee, when I was attended last committee my knowledge level increased and got a clear picture about my topic and now I knew as a researcher this information sheet is very essential to conduct their study and without information sheet can not conduct a research. Now I feel more confidence to speak and I can stick my opinion. When I attended ethics committee, I had both good and bad experience. While I am a member of ethics committee, helped me to learn some new ideas and analyzed and interpret each and every matter we discuss in the committee .Before I joining ethics committee I am always feel shy and introverted in social life, but once I actively joined with the ethics committee I become more extroverted and learned how to express my ideas according to my goals. It is clearly evidence in social participitation theory (Srivastava, Angelo, and Vallereux 2008) and helped me to how introverted person can be extroverted or social being. Then started referred different book, journals and even learn to browse internet to get a suitable point and skills to make me more confidence and accurate .The bad experience about committee, even if I prepared well with best of my knowledge, even then also while discussing with others they night have different ideas or views that make me confused weather my points were rig ht or wrong .Hence I still I have confusion in terms in philosophical paradigm and hypothesis. The situation was made good in my own research proposal and helped me to increase my knowledge about my dissertation topic. Knowledge and experience can make the researcher could perform more accurate and successful.(Verburg Andriessen,2011) To me as a learner this knowledge is essential for my research proposal and can prepare a good project. When I started to attended the first committee I thought in research’ Participant information sheet ‘is not much important role just we should invite the participants to take part in our research study .But now recognized without information sheet the research proposal is invalid and all information regarding the participant details will be handled in confidence. I can make a good research which I collected from information sheet. I got all sort of different necessary information from each sheet and I am confident that I can design a better quality research proposal as a part of my research. Each and every participant, who became a member in the research team, should have the aware about their rights and also very important to ensure their safety and dignity. There are six ethical principles can use to protect their participants from harm (ICN, 2003).However there are three rights for every researcher who actively involve in research: privacy, safety and dignity. It is important to keep the confidentiality which we get through participant information sheet. As a researcher every one must keep the anonymity without revealing their names. It’s a protocol to keep the patient details recorded in appropriate manner and it should be separated in different file with proper label and it must be in their cupboard or cabinet which is only accessible to authorized person. It is very essential to respect and keep the dignity for each and every person. While conducting any research, it’s necessary to explain about the purpose and reason for conducting particular researc h to every participant In retrospect, I am planning to do many things in different way. I have been more confidence and should be more proactive myself. I have discussed to the ethics committee members as soon as finishing the committee and I can contribute my opinion. However I learned from the incident is I should be more courage and I have to maintain a good relation with our supervisor in the coming weeks, so that I could do in a best way in committee. In future, I would ensure I will be more confident about research proposal either in qualitive or quanitive, especially in my particular aspect ‘information sheet. I am studying alongside with different teachers during my course, and I will speak about my nervous. I have already personal tutors and I have communication with her, and she helped me a lot to achieve my goal and how to present very well in future, so that I do not feel so nervous. I also want to share with my colleagues about my feelings and I think it will help to study from them. For training purpose I focused to attend in seminar when they were conducting in Teesside University and I want to achieve more confidence and this is the good method to improve my presentation skill. This reflective essay enhanced my level of thinking, knowledge and understanding its importance, had improved with use of reflective model .My competence level has also developed especially the ability to do my presentation in best way to begin. REFERENCES Parahoo, k. (2006) Nursing Research. Principles, process and issues.2nd ed .Hampshire: Palgrave Macmillan. Corti, L., Day, A. Backhouse, G. (2000) Confidentiality and Informed Consent: Issues for Consideration in the preservation of and provision of Access to Qualitative Data Archives. Forum Qualitative Social Research.1 (3) p2-4. Tolich, M.(2009)The principle of cavet emptor: confidentiality and informed consent as endemicethical dilemmas in focus group research. Journal of bioethical inquiry.6 (1) p99-108. Knowledge sharing, Personality Traits and diversity. Available at: http//www.lindenwood.edu/mwr2p/docs/Amayah.(Accessed 5.5.14) Reserach ethics policy: Participiant safety and wellbeing. Available at: http: //www.sheffield.ac.uk/ris/other/gov-ethics.(Accessed 2.5.14)

Processing Emotions in Mrs. Dalloway and Demonology :: Virginia Woolf Rick Moody Social Classes Essays

Processing Emotions in Mrs. Dalloway and Demonology Hold them in or let them out; typically these are the only two options one has in dealing with their everyday emotions. Over time, making this decision has differed greatly. The transition between holding in your emotions and letting them out can be seen between two writers from two different eras. In Virginia Woolf’s Mrs.Dalloway, she portrays people in upper class England during the first half of the 20th century and how they process their emotions. Then, in Rick Moody’s short story Demonology he reveals how an average American family during the latter half of the 20th century chooses to handle their emotions. These two stories are perfect examples of how different eras dealt with their feelings in a completely different manner. There can be many connections drawn between these two stories as to the situations the characters are living in and what they have to deal with. Given that they each take place in completely different time periods, the story lines act as a steady base to make judgments as to how they handle their emotions. The story lines also act as a reliable source as to what was going on during each time period. So with these two books, we are able to take them out of there context and actually view them as real life history. By doing this we are able to compare the two different eras and see how they decided to handle their emotions. To begin comparing these two stories, the easiest comparison that is made is that both are stories that are based in one day. This allows us to see how they react to everyday situations. Second, they both deal with people conversing amongst one another. Each person has an image to up hold throughout the two stories. This is most apparent in Mrs. Dalloway since the main character is always trying to uphold her status amongst her social bracket. This is also the case in Demonology where the narrator’s sister is living the typical materialistic American life style, be it through her kids or simply her decisions on anything she does. Finally, these two stories allow us to see how people handle themselves when confronted with marital issues and most importantly how they deal with tragedy. All of these comparisons set the stage for an open look as to what each author and era had to deal with and the way they went about it.

Animal Farm, by George Orwell :: Animal Farm Essays

One of the things I like about small presses is that they'll take chances on authors who write about things outside of the mainstream. III Publishing has been one of my favorite sources for libertarian/anarchist fiction and science fiction ever since I picked up and totally enjoyed The Last Days of Christ the Vampire. Now they bring us two fine contributions to anarchist SF literature. If you loved George Orwell's Animal Farm, you'll love this "sequel." Many who have read Orwell's classic missed the basic underlying anti-authoritarian message, instead reading it as an allegory about the Soviet Union. In Anarchist Farm we find an extension of the philosophies underlying Animal Farm, but this time with a more upbeat outcome. Contemporary concerns such as ecocide and animal rights are also woven into this readable book. In fact, it is written in a style appropriate for teenage readers. As in Animal Farm, the main characters here are animals and they talk. They also have cute names. Pancho is a pig who has escaped from the regime that has taken over the farm portrayed in Animal Farm. He is befriended by some wild animals, who are later revealed to be the "Forest Defenders." The Defenders turn out to be very similar to Earth First! Pancho eventually finds a farm whose owner has recently died. In response to the death of their benevolent owner, the animals turn the farm into a successful anarchist collective. As the months roll by, the animal start to worry about what might happen to them when the humans come to auction off the farm. The ending will surprise you. It should also be mentioned that the book also deals with monkeywrenching and its consequences. Anarchist Farm is funny, thought-provoking, and inspiring. It's an excellent sequel to Animal Farm. Let's hope that a few more readers "get it" this time. A.D. is a science fiction story set in the U.S.A. in the near future. Radical changes have altered the very political geography of the continent: the Klux Klan Klan and other white supremacists control what was the southern U.S., the Nation of Islam controls what was the Midwest, and the West Coast is all that remains of the old U.S. "liberal democracy." Fred Hampton Rush Sr. is a middle-aged black man living in Chicago, which is now the capital city of the Lost-Found Nation of Islam in North America.

The Effect of Humour in Galloway’s the Cellist of Sarajevo

People of all ages and cultures respond to humour. Riddles and jokes have been told for centuries to make light of situations and to make people laugh. Humour is the tendency of particular experiences to provoke laughter and provide amusement. People are able to be amused, laugh, or smile at something funny, and therefore they are considered to have a sense of humour. To find something humourous depends on the person and their taste in humour and there are many instances when humour does not result in laughter because of the mood of the surroundings or the context. Humour is an emotion that enables us to experience joy even when faced with adversity. It can be seen that in Galloway’s The Cellist of Sarajevo, humour is used in a dark way to lighten the mood. This is done so that the readers have glimpses of light in a dreary time. Humour helps people, in this case the characters, carry on their lives in times of adversity. Galloway uses the lives of Kenan and Dragan to exemplify how humour, in the slightest form, can make a dreary day a little more pleasant. Through examining the life of Kenan, a middle aged man, it will be proven that humour has an important role in his daily life. Kenan has the duty of carrying canisters to the brewery to bring clean, filtered water for his family and Mrs. Ristovski, the neighbour. Before the war, Kenan was a clerical assistant at an accounting firm. His journey to the brewery is very risky because at any point he may be shot; therefore, humour has a huge impact in the way Kenan presently lives his life. Before Kenan leaves his house his wife and him joke about their clothes: â€Å"Would you like me to get you some shoes?†¦ No, she says. But I’ll take a hat if you have time†¦ Of course, he says. I would assume you would like mink? † (Galloway, 26). At a time of war, fancy clothes will not benefit either of them, but he leaves his wife in a good mood. Amila and Kenan use light humour to make a dark situation a little easier to bear. Another example in which Kenan uses his humour to make his grey, dreary journey a little more pleasant is when he walks across an older man fishing for pigeons: â€Å"How’s the fishing today? Kenan asks, †¦ They’re biting well, the man says, †¦ Do you need a licence this time of year? e asks, smiling so the man understands it’s a joke† (Galloway, 64). Seeing the man fishing for pigeons was a brief distraction for Kenan and also a window of hope; with seeing the man, Kenan felt that if he could finish his mission of collecting water for his family, he could also fish for pigeons to help his family. The humour is light; it makes the reader pause, and makes the characters forget about th eir surroundings and just smile. Kenan made slight of the situations he faced so that he can smile, and make it seem that life will carry on with the war. Just as Kenan used humour in his life, Dragan, previously a baker does the same to fill the void of his missing son and wife who left on the last bus to Italy. Dragan now lives with his sister and her family, and to have his space he goes to collect bread from the bakery for the family. While on his journey he has seen many men and women running to cross roads so that the snipers have less probability of hitting them. Dragan likes to see the running as a game: â€Å"The man runs in a straight line. He’s fast. A new world record? Maybe. Perhaps they will have to notify the people at Guinness† (Galloway, 230). Dragan uses sarcasm to make an almost dangerous situation seem funny since the civilian has survived. Dragan likes to see things for what they are, and to make the most of a situation. There is no need to focus on the bad when there is also much to be grateful for. Just like Kenan, Dragan does face a lot of danger and hardships with dealing with the loss of his family, but his humour and sarcasm seem to help him push through and carry on with his life. Dragan uses his wit make it through the tough and challenging times, especially since he has no one by his side. Although Galloway’s The Cellist of Sarajevo is about a devastating, tragic time in history, he manages to use humour in the characters to lighten the mood of the book. By examining how Kenan and Dragan use humour, it has been shown that humour assists in fighting adversity. No matter what situation the character was faced with, they still had their humour, and as long as their sense of humour was alive, their sense of hope would live. As the humour helps the characters in the novel, it also makes the readers have something to tone down the darkness and despair of reality of the war. All persons are different and have appeal to a different sense of humour, but as long as there is something to put a smile on one’s face, then there is something worth fighting for. Works Cited Galloway, Steven. The Cellist of Sarajevo. Toronto, Vintage Canada, 2008 â€Å"Humour. † Wikipedia: The Free Encyclopedia. Wikimedia Foundation, n. d. Web. January 30, 2010

Microscopes and Microscopy

Microscopes and Microscopy Introduction The purpose for including a lab on microscopy in his course is because it is a very important tool in making detailed observations. This lab helps the average person realize that there is much more to things than what you see with the naked eye. In the field of human biology microscopes are very important for many reasons. In the late 1500’s a scientist named Zacharias Janssen created the first microscope of it kind and now we have several microscopes that are very important to the study of human biology. The compound microscope is used to view individual cells as well as living cells such as hair. Electron microscopes can be used to view things such as biological tissues and organisms. Also, another popular microscope used in human biology is the stereo microscope, which is commonly used to dissect and examine human tissue. Discussion When studying the â€Å"optics† slide in the interactive section of this lab it displayed image orientation. To display this it took the letter â€Å"e† and showed you the standard view to the naked eye and then it showed you the view through a light microscope and it looked very different. The â€Å"e† was upside down and backwards left while looking down in the microscope. The reason it looked like this was because of the shape and lenses in the microscope. While studying the color threads on the interactive microscope you notice that the colors are red, green, and yellow from top to bottom. The magnification that was useful in helping me determine the order was 400x. This magnification allowed me to see that the yellow color thread was on the bottom and that the green color thread was in the middle. The optical principles that are in play here are perfect lens characteristic and transmitted light microscopy optical pathways. Interpupillary distance is the distance between the centers of the pupils of the two eyes. The way to determine what the interpupillary distance is with a device called a pupil meter. This device presents a binocular subject that can be set from a close viewing distance out to optical infinity. The diopter setting is a control knob on a microscope that helps your eyes view something similar in proper relation instead of allowing each individual eye to view the subject differently. It is necessary to locate an object using the low objective because it allows you to gain a better focus before switching to the high power objective and makes it so you don’t have to make much of an adjustment on the high power objective. Just trying to focus using the high power objective could get very time consuming. Reducing the iris diaphragm aperture on a microscope will clarify an image focused under high power, but it would be letting less light in the field of view. The reason it would clarify the image is because under high power it doesn’t take much light to bring whatever you are viewing into focus due to the strength of the lens. If my lab partner was having problems locating onion cells using a parfocal microscope with the low power objective and just switched to the high power objective I would tell her that this is an incorrect way to bring the onion cells into focus. I would advise her that she would need to continue to bring the onion cell into focus with the low power objective because once you have it in focus with the low power objective you can switch to the high power objective with out making any changes to the focus. I am striving to become a nurse and I believe that in that career field it is extremely important for me to be especially knowledgeable regarding microscopy. While working as a nurse it is going to be extremely important for me to know what microscopes are going to be best to use in certain circumstances. For my career field it is going to be very important to understand how to use a microscope and that goes for knowing how to bring cells into more focus as well as knowing that I need to bring what I am viewing into focus under the low power objective.

Gang Development And Control Essay

Below are descriptions of gang development theories. Copy and paste the correct description into the table below next to the appropriate theory. There are five descriptions and four theories. One description is not valid. Theory Gang members are violent and rarely show remorse or feelings regarding their violent and criminal actions. Members may join a gang because it provides them a release for their personal problems, which may include drug abuse, low self-esteem, and family problems. Gang members typically come from low income areas and may even be considered to have been â€Å"forced† into gang life in order to survive. The gang provides a sense of belonging in a world where members may lack positive role models and the ability to attain status in a way considered acceptable by society. Joining a gang is a way to obtain money and protection. It is often seen as a personal decision to gain success. Members who join for this reason feel pride when they get away with a crime and were most likely committing illegal acts long before joining a gang. Members join a gang to have a safe social circle and to learn techniques to communicate through graffiti. Gang members use those techniques to display their gang’s strength and power in their neighborhood. Members who join a gang for this reason are typically involved in drug use and truancy but rarely violent acts of delinquency. Individuals who join gangs for this reason may have an older family member who is a gang member. They may go through distinct hazing rituals before they can join. The hazing rituals offer assurance that the individual is capable and ready to start his or her new life as a gang member. Description: Anthropological †¢Individuals who join gangs for this reason may have an older family member who is a gang member. They may go through distinct hazing rituals before they can join. The hazing rituals offer assurance that the individual is capable and ready to start his or her new life as a gang member. Sociocultural †¢Gang members typically come from low income areas and may even be considered to have been â€Å"forced† into gang life in order to survive. The gang provides a sense of belonging in a world where members may lack positive role models and the ability to attain status in a way considered acceptable by society. Psychological †¢Gang members are violent and rarely show remorse or feelings regarding their violent and criminal actions. Members may join a gang because it provides them a release for their personal problems, which may include drug abuse, low self-esteem, and family problems. Rational Choice †¢Joining a gang is a way to obtain money and protection. It is often seen as a personal decision to gain success. Members who join for this reason feel pride when they get away with a crime and were most likely committing illegal acts long before joining a gang. Gang Control In the table below, describe the gang control methods in your own words and use the Internet to provide an example of a program based on each type of gang control method. Include the name of the Web site and the working URL address in the table. Gang Control Methods Descriptions Examples Law Enforcement Efforts Law enforcement is looked at for gang control and it takes three forms. Youth service program where they are given responsibility for gang control. Gang details are assigned exclusively to gang control work. Gang units are to deal solely with gang problems. Chicago officers have an intelligence unit that will use the gang members name in the computer to see if they have gotten arrested or picked up for anything. Gang Awareness https://portal.chicagopolice.org/portal/page/portal/ClearPath/Communities/Gang%20Awareness Community Control Efforts They used to have the YMCA where there were people there to work with gangs. Now they have prevention services for kids to prevent them from joining a gang. Like counseling and parent kid activities. They also want to find a way to involve programs into the schools. Gang Free http://www.gangfree.org/who_index.html