Virtual Reality Research Paper Example | Topics and Well Written Essays - 2500 words

Virtual Reality - Research Paper Example These applications range from educational to health systems. However, the technology also has harbored some disadvantages due to its application. This paper delves into the topic of Virtual Reality. It examines some of its uses, its disadvantages as well as challenges that hinder its effective application. Introduction Virtual reality is a three-dimensional environment. One can only view it on a computer screen or through special goggles. Besides, one can relate with the virtual world as if one is part of it using specially designed equipment (Owens, 2010). According to Isdale (1993), virtual reality is a means for individuals to manipulate, interact and visualize with extremely complex data and computers. In this case, visualization part talks about the computer producing auditory, visual or other sensual outputs to a human being within the computer. This world could be a scientific simulation, a view into a database, or a CAD model. Conversely, the user can relate with the world an d directly and control objects within the world. In addition, other processes like simple animation scripts or physical simulations animate some worlds. With virtual reality, there is a likelihood of custom-designed while the three-dimensional environments permit instinctive â€Å"transparent† boundaries such that the computer interface is imperceptible to the user. In addition, virtual reality allows for considerably improved three-dimensional perception and interaction over conventional three-dimensional computer graphics because of its interaction capabilities and three-dimensional display (Bryson, 1996). On the other hand, VR can also be useful in an advanced user interface to three-dimensional simulation models in simulation terms (Barnes, 1996). Moreover, there are various fields in which VR applications have significant potential including medicine, industry, education and training, commerce, entertainment industry, scientific research and the space. On the other hand, to make innovations that use VR technology effective, there should be a thorough exploration. However, VR is still immature both as a technology and as a field of research. As a result, there should be considerable research to be done to realize the full potential of VR (Barrett, 2004). This is the reason the electronic and computer engineers are pursuing new ways of improving the virtual reality experience. Presently, computer and electronic scientists and engineers are developing a system that will incorporate the sense of taste (Lee, 2011). Applications and equipment for Virtual Reality Several technologies are requisite for the creation of a virtual world each of which, have advanced technologically and independently. The heart of virtual reality is a combination of software, hardware and electronics. These three computers related technologies merge to make virtual reality work. In addition, three imperatives are essential to help virtual reality work including special software , the individual user and a computer. Moreover, there are several input devices to improve the virtual reality experience and enable it to work. These input devices help in recording, measuring electronic signals, and converting them into a physical world. On the other hand, the output devices allow the user's brain to process the computer-generated physical world created. However, the reality engine is the main power of a virtual reality system. This engine helps create the virtual world and process information. It comprises either a group of computers or one powerful computer because the reality engine is supposed to create complex graphics (Lee, 2011). However, the virtual reali

Maritime law Coursework Example | Topics and Well Written Essays - 1000 words

Maritime law - Coursework Example This is the absolute duty that the ship or the vessel owner owes to the seamen who are involved in the voyage, for the protection of any risk that might face their lives emanating from the unworthiness or lack proper maintenance of the ship. Thus, if any event of collision or accident occurs in the sea, due to the un-seaworthiness of the ship or the vessel, then the owner of the ship or the vessel is liable for the damage, and the appropriate liabilities shall befall the owner3. This includes the liabilities of all the damages incurred on the cargo, the seamen or the other ships or vessels that could have collided with the unseaworthy ship or the vessel, during the course of their voyage. Among the cardinal duty of the ship or vessel owner is to provide a seaworthy ship or vessel. The doctrine of seaworthiness is the cardinal principle of the Maritime law, considering that the issue of seaworthiness of a ship or a vessel directly affects the liabilities of various stakeholders in the Maritime Law, who may include the liability of the carrier, the marine insurance and the environment4. The concept of seaworthiness of a ship or a vessel is provided under the law, as the presence of all pipes, pumps, heater coils and all the other components of the ship or the vessel, which are in good working order. Thus, the law is further interpreted to mean that the fundamental responsibility of the ship or the vessel owner, which he owes to the seamen; both operating the ship he owns or the seamen operating other ships or vessels on the water body, is to ensure that the ship or the vessels are fit to undergo the hazards of the sea, or any other incidental risk that may occur along the voyage, which the ship or the vessel might be exposed in the course of the voyage, without necessarily having such risks being contributed in any way, by the un-seaworthiness of the ship or the vessel6. This being the case, the owner of the ship bears all the liability in case of an accident, co llision, damage or injury occurring to the vessels, the ship or the seamen, which emanates from any aspect of the ship being unworthy for the sea voyage. However, as s reprieve to the owner of the ship or the vessel to be involved in a voyage, the concept of seaworthiness of the ship or the vessel was lessened only to include the worthiness of that ship or vessel, at the start of the voyage2. Therefore, while there are many instances that may arise where a vessel could be identified as being unseaworthy, the only liability that the owner of the ship or the vessel can bear, is that of the ship or the vessel being unseaworthy at the start of the voyage, while the other aspects of un-seaworthiness, which might occur in the course of the voyage, are deemed incidental and thus the liability is assessed differently3. According to the provisions of the Maritime law, there are several conditions that may constitute the un-seaworthiness of the ship or the vessel in voyage. First, a stowage w hich may affect in any way the safety of the ship or the vessel is considered unseaworthy, and thus constitutes the un-seaworthiness condition of the ship or the vesse7. Secondly, any deficient systems ashore or on board the ship or

Oncogenes and Breast Cancer Term Paper Example | Topics and Well Written Essays - 1500 words

Oncogenes and Breast Cancer - Term Paper Example Thus, classification of tumors in diverse types and subtypes along with the identification of individuals who are at the potential risk of cancer is gaining prevalence. A combination of data procured from gene-expression and genomic information aids in the detection of possible new targets for designing high-throughput screening strategies for designing drugs that will lead to advances in cancer cell-targeted therapy. The present article deals with the importance of understanding for oncogenes to comprehend breast cancer. Introduction Cancer is known as malignant neoplasm, the hallmark characteristic involves uncontrolled proliferation of cells. Under normal conditions cells grow, divide and die, but in a genetic defect called mutation occur in cancer cells leading to the formation of an abnormal DNA. As genes are the basic control machine of the cells, alteration of any kind may bring devastating consequences, or malignancy. When compared with the normal cells, where damage of any k ind is taken care by the repair system, tumor cells do not have any repair mechanism for the damaged DNA and there is a constant proliferation of cells without displaying senescence hence, generating a series of abnormal cells, with altered cellular pathways for uncontrolled proliferation, figuring malignant tumors (Alberts 2007; Katzang et al. 2009). (Normal cell cycle) (Genetic mutation- causes alteration in genes) (Alberts 2007) Cancer cells manifest, to varying degrees, four characteristics that distinguish them from normal cells, comprising- uncontrolled proliferation, de-differentiation and loss of function, invasiveness and metastasis (Rang et al. 2007). The Genesis of a Cancer Cell A normal cell turns into a cancer cell because of one or more mutations in its DNA, which can be inherited or acquired. In case of the breast cancer, woman who inherits a single defective copy of either of these tumor suppressor genes BRCA1 and BRCA2 displays an augmented risk of developing breast cancer. However, carcinogenesis is a complex, multistage process, usually involving more than one genetic change. Other epigenetic factors responsible for carcinogenesis involve epigenetic factors, such as level of hormones in the body, exposure to carcinogens and tumor promoting agents. These epigenetic factors do not produce cancer by themselves but enhances the likelihood of genetic mutation(s) resulting in cancer. These genetic changes are categorized as - A. The activation of proto-oncogenes to oncogenes: Proto-oncogenes are the normal genes present in the cells and are responsible for controlling cell division, cell differentiation and apoptosis. A triggering factor such as a virus or exposure to any carcinogen brings malignant changes in the cell. B. The inactivation of tumor suppressor genes: A cell has the mechanism to protect itself from uncontrolled proliferation and tumor formation due to expression of genes called tumor suppressor genes. These genes possess the ability to suppress malignant changes and are also referred as antioncogenes. Mutation in proto-oncogenes or tumor suppressor genes results in the proliferation of tumor. Thus, a loss of function of tumor supp

Based on your ideas on Nilsen and Tannen, discuss how language Essay

Based on your ideas on Nilsen and Tannen, discuss how language reflects patriarchy (Patriarchy) - Essay Example Besides, she manages to show that even when filling forms, women tell stories about themselves because most forms offer four titles to choose from and they include â€Å"Mr.†, â€Å"Mrs† or â€Å"Miss† and â€Å"Dr†. In her work, â€Å"Mr.† â€Å"carries no meaning other than that the respondent is male† (Tennen395); however, when women accept â€Å"Mrs.† or â€Å"Miss† it shows that they have been married and that they have conservative forms of address. Women using the label â€Å"Ms.† decline to reveal if they are married while men using the title â€Å"Mr.† decline nothing considering that nothing was asked; hence, women using â€Å"Ms.† tend to be seen â€Å"as either liberated or rebellious depending on the observer’s attitudes† (Tennen395). Tennen shows that married women surnames are marked and that if a married woman accepts her husband’s name, she acknowledges to the world that , â€Å"she is married and has traditional values† (Tennen396). ... From her dictionary cards, Nielsen shows that â€Å"feminine words have acquired sexual connotations while the masculine word retains serious business like aura† (Nielsen). For instance, she manages to show that while a callboy is an individual who calls actors when time comes for them to go to stage, a call girl is considered a prostitute. In her study, Nielsen found about 200 pairs of words that accepted both masculine and feminine forms and in nearly all of the pairs, masculine form was considered the base where a feminine suffix was added. The masculine form is basis on which compounds are made apart from one semantic area where masculine word is not the basis and the areas deals with sex, marriage and motherhood. Nielsen shows that when someone refers to a virgin, the listener probably considers a female unless the speaker specifies a masculine pronoun, which is the same case with the term prostitute. Moreover, Nielsen shows that the grammar used in writing or even talkin g about weddings show the expectation of men playing an active role when men wed women while the women become brides of men. Nevertheless, titles offered to royalty indicate that males can be at loss because of the assumption that they predominantly play a powerful role; for instance, when a female has the royal title, then the man she marries does not automatically acquire a matching title. From Nielsen’s article, it is clear that connotations between encouraging male and pessimistic female connotations can be established from various pairs of words that differ denotatively in the area of sex. For instance, patron and matron have varying degrees of esteem that womenfolk attempt to use the

Organizing Function of Management Essay Example | Topics and Well Written Essays - 2000 words

Organizing Function of Management - Essay Example Organizing is a broad set of activities, and often considered one of the major functions of management" (McNamara 2007). In the Department of Veterans Affairs, organizing function has a great impact on HR and staff relations. In this organization, HR is concerned with a long-term and a short-term perspective; the psychological contract based on commitment and compliance; self-control and external controls. The Department of Veterans Affairs pays a special attention to selection process and development of employees who work with veterans and their families. Organizing function involves training programs for service workers and career development, promotion and personal development of employees. The core of organizing function of HR includes communication, motivation and leadership (Horts, 2002). Within the Department of Veterans Affairs, attention is also drawn to the key role of organizational culture. For example, an "organization" means the philosophy, attitudes and actions of top managers and service workers, or possibly an individual manager. The rationale for organizing function is built on the idea that employees and clients engage in basically consistent, value-maximizing calculations or adaptations within certain constraints. The peculiarity of this organization is that it deals with diverse customer groups and services. In many cases, the Department of Veterans Affairs has to choose the alternative approach and consequences that rank highest in terms of the payoff functions; that is, that contribute most to the ultimate goal (Horts, 2002). The organization introduced additional training focusing on employee's motivation and work design programs to help worker identify their goal and professional development strategies. Organizing function helps to determine and ma nage goals or objectives and has a payoff, utility, or preference function that permits that person to rank all possible alternative actions by the action's contribution to the desired goals. For instance, "HSR&D provides core funding to fifteen Centers of Excellence (COEs). The research at each COE serves to energize the facility and network with which they are affiliated, and provides a constant source of innovation, creativity and support" (the Department of Veterans Affairs 2007). The organization is presented with and understands alternative courses of action. Each alternative has a set of consequences. Successful organization performance depends upon and is determined by technology. For instance, "technology as it is used in health care is defined as applied knowledge, in other words: any intervention used in health promotion, prevention and rehabilitation" (the Department of Veterans Affairs 2007). Technology helps to connect people in organization who operate in a distance, and has no opportunity to use printed matters or other sources. Organizing function plays a crucial role in technology management determining the main areas of improvement and resources available and needed for this process. The key benefit is the fast interactions between employees and between employees and clients. This constitutes the capital of an organization, i.e. the network of relationships constitutes a valuable resource for the conduct of organizational affairs. For

My Experience with Mother Hens and Their Families Essay Example for Free

My Experience with Mother Hens and Their Families Essay The purpose of our sanctuary on the Virginia Eastern Shore is to provide a home for chickens who already exist, rather than adding to the population and thus diminishing our capacity to adopt more birds. For this reason we do not allow our hens to hatch their eggs in the spring and early summer as they would otherwise do, given their association with the roosters in our yard. All of our birds have been adopted from situations of abandonment or abuse, or else they were no longer wanted or able to be cared for by their previous owners. Our two-acre sanctuary is a fenced open yard that shades into tangled wooded areas filled with trees, bushes, vines, undergrowth and the soil chickens love to scratch in all year round. It also includes several smaller fenced enclosures with chicken-wire roofs, each with its own predator-proof house, for chickens who are inclined to fly over fences during chick-hatching season, and thus be vulnerable to the raccoons, foxes, owls, possums and other predators inhabiting the woods and fields around us. I learned the hard way about the vulnerability of chickens to predators. Once, a hen named Eva, who had jumped the fence and been missing for several weeks, reappeared in early June with a brood of eight fluffy chicks. This gave me a chance to observe directly some of the maternal behavior I had read so much about. We had adopted Eva into our sanctuary along with several other hens and a rooster confiscated during a cockfighting raid in Alabama. Watching Eva travel around the yard, outside the sanctuary fence with her tiny brood close behind her, was like watching a family of wild birds whose dark and golden feathers blended perfectly with the woods and foliage they melted in and out of during the day. Periodically, at the edge of the woods, Eva would squat down with her feathers puffed out, and her peeping chicks would all run under her wings for comfort and warmth. A few minutes later, the family was on the move again. Throughout history, hens have been praised for their ability to defend their young from an attacker. I watched Eva do exactly this one day when a large dog wandered in front of the magnolia tree where she and her chicks were foraging. With her wings outspread and curved menacingly toward the dog, she rushed at him over and over, cackling loudly, all the while continuing to push her chicks behind herself with her wings. The dog stood stock still  before the excited mother hen, and soon ambled away, but Eva maintained her aggressive posture of self-defense, her sharp, repetitive cackle and attentive lookout for several minutes after he was gone. Eva’s behavior toward the dog differed radically from her behavior toward me, demonstrating her ability to distinguish between a likely predator and someone she perceived as presenting no dire threat to her and her chicks. She already knew me from the sanctuary yard, and though I had never handled her apart from lifting her out of the crate she’d arrived in from Alabama several months earlier, when I started discreetly stalking her and her family, to get the closest possible view of them, the most she did when she saw me coming was dissolve with her brood into the woods or disappear under the magnolia tree. While she didn’t see me as particularly dangerous, she nevertheless maintained a wary distance that, over time, diminished to where she increasingly brought her brood right up to the sanctuary fence, approaching the front steps of our house, and ever closer to me but not too close just yet. When she and her chicks were out and about, and I called to her, â₠¬Å"Hey, Eva,† she’d quickly look up at me, poised and alert for several seconds, before resuming her occupation. One morning, I looked outside expecting to see the little group in the dewy grass, but they were not there. Knowing that mother raccoons prowled nightly looking for food for their own youngsters in the summer, I sadly surmised they were the likely reason that I never saw my dear Eva and her chicks again. Inside the sanctuary, I broke the no chick-hatching rule just once. Upon returning from a trip of several days, I discovered that Daffodil, a soft white hen with a sweet face and quiet manner, was nestled deep in the corner of her house in a nest she’d pulled together from the straw bedding on the dirt floor. Seeing there were only two eggs under her, and fearing they might contain embryos mature enough to have well-developed nervous systems by then, I left her alone. A few weeks later on a warm day in June, I was scattering fresh straw in the house next to hers, when all of a sudden I heard the tiniest peeps. Thinking a sparrow was caught inside, I ran to  guide the bird out. But those peeps were not from a sparrow; they arose from Daffodil’s corner. Adjusting my eyes, I peered down into the dark place where Daffodil was, and there I beheld the source of the tiny voice a little yellow face with dark bright eyes was peeking out of her feathers. I kneeled down and stared into the face of the chick who looked intently back at me, before it hid itself, then peeked out again. I looked closely into Daffodil’s face as well, knowing from experience that making direct eye contact with chickens is crucial to forming a trusting, friendly relationship with them. If chickens see people only from the standpoint of boots and shoes, and people don’t look them in the eye and talk to them, no bond of friendship will be formed between human and bird. I’ve seen this difference expressed between hens we’ve adopted into our sanctuary from an egg production facility, for example, and chickens brought to us as young birds or as someone’s former pet. Former egg-industry hens tend to look back at me, not with that sharp, bright, direct focus of a fully confident chicken, but with a watchful opacity that no doubt in part reflects their having spent their entire previous lives in cages or on crowded floors in dark, polluted buildings that permanently affected their eyes before coming to our sanctuary. Psychologically, it’s as if they’ve pulled down a little curtain between themselves and human beings that does not prevent friendship but infuses their recovery with a settled strain of fear. I’ll say more about these hens presently. From the very first, a large red rooster named Francis regularly visited Daffodil and her chick in their nesting place, and Daffodil acted happy and content to have him there. Frequently, I found him quietly sitting with her and the little chick, who scrambled around both of them, in and out of their feathers. Though roosters will mate with more than one hen in the flock, a rooster and a hen will also form bonds so strong that they will refuse to mate with anyone else. Could it be that Francis was the father of this chick and that he and Daffodil knew it? He certainly was uniquely and intimately involved with the pair, and it wasn’t as though he was the head of the  flock, the one who oversaw all of the hens and the other roosters and was thus fulfilling his duty in that role. Rather, Francis seemed simply to be a member of this particular family. For the rest of the summer, Daffodil and her chick formed a kind of enchanted circle with an inviolable space all around themselves, as they roamed together in the yard, undisturbed by the other chickens. Not once did I see Francis or any of the other roosters try to mate with Daffodil during the time she was raising her frisky chick the little one I named Daisy who grew up to be Sir Daisy, a large, handsome rooster with white and golden-brown feathers.

The Discovery Telomerase Essay Example for Free

The Discovery Telomerase Essay The linear chromosomes of eukaryotes are more complex than the circular chromosomes of the bacteria. Due to the biochemical properties of DNA polymerases, the replication of the eukaryotic chromosomes poses a special problem: the maintenance of the length of the linear chromosomes. However, it was discovered that a unique enzyme complex appears to play a crucial in maintaining the length of eukaryotic chromosomes. This enzyme is known as the telomerase. Its regulative action on the eukaryotic cell implies that it may also be involved in the process of aging and in the development of cancer cells. In this paper, the telomerase becomes the focus of study. The discovery, properties, and functions of the telomerase inside the eukaryotic cells will be described, based on the recent scientific studies that have been conducted about them. And finally, current and potential applications that involve this enzyme, in the field of biotechnology, will be presented. The Discovery of Telomerase When the telomerase was first discovered by Carol Greider in 1984, many geneticists and molecular biologists like her have already been puzzling over the observation that the tips of chromosomes are stabilised by telomeres. Telomeres are mere regions in the DNA in which sections of them are no longer copied during the process of cell division and chromosome replication (Vermolen 2005). But the fact that a small section of a telomere is not copied should result in shorter telomeres in the daughter cells. Strangely, this does not occur and scientists can only surmise that something maintains the length of the telomere and it could be an enzyme that is yet unknown. Then, on that fateful Christmas Day in 1984, Greider found the elusive enzyme through the use of autoradiography (Skloot 2001). The telomerase is the enzyme that is responsible for maintaining the genetic material found at the tips of the chromosomes. The Properties of Telomerase The telomerase is an enzyme and this brings to mind two basic characteristics. First, any enzyme is composed of a protein. In the case of telomerase, the protein is the RNA and it can be considered as a ribozyme (Brown 2005). And second, any enzyme is a natural catalyst of all chemical reactions within the body of an organism. This means that the telomerase facilitates a vital biochemical reaction. But the exact mechanism that the telomerase executes to maintain the length of the telomere during chromosomal replication can only be determined if the properties of it are known. And the properties can be known if the specific nature of the structure of the RNA is established. The telomerase is composed of two components, the essential RNA and the TERT. The latter, which stands for telomerase reverse transcriptase, is the catalytic protein. It â€Å"contains sequence motifs homologous to those in the catalytic domain of reverse transcriptase enzymes† (Chen Greider 2004, p. 14683). This is concluded because the TERT is remains the same in all eukaryotes. The structure of the RNA component, however, is more challenging to characterise. This is because the telomerase RNA varies in terms of size and sequence. Fortunately, the overall structure of the telomerase RNA in many ciliates and vertebrates was eventually established (Chen, Blasco Greider 2000). The common process utilized was the phylogenetic analysis (Tzfati 2003). However, the characterization of telomerase RNA did not reveal similarities. There are large differences among the telomerase RNA structures of different organisms. For example, the RNA of ciliates has a conserved sequence motif found in helix I (Lai 2002), where as the RNA of yeasts seeks several helical regions as the binding sites for the telomerase’s Est1 protein (Peterson et al 2001). Thus, there was a need to ascertain a core structure. This core structure is also referred to as the secondary Blackburn (2004) and her colleagues, by using telomerase RNAs of yeasts, proposed a core structure out of the process of delineating nucleotides and base pairings. They showed that a pseudoknot structure is an essential component of the telomerase RNA because it plays an important role during the binding process. Figure 1: The TERT binding and the pseudoknot The Functions of Telomerase The most obvious function of the telomerase, as stated before, is the maintenance of the length of the linear chromosomes of eukaryotes. This is carried out through a process known as reverse transcription. But, among scientists, this general statement is insufficient, especially before the advancing knowledge in biochemistry. And now that the structure of the telomerase is established, the next question to be answered is how the telomerase actually and specifically works. There is no consensus so far, but the results of various studies can be combined to form a better picture of the function of telomerase. Here are three of the most significant ones. First, it was firmly established by several studies that there is a long-range base-pairing that occurs at the Est2 binding site (Chappell Lundblad 2004; Dandjinou et al 2004; Lin et al 2004; Zapulla Cech 2004). Second, the pseudoknot performs various functions: binding at Est2 among yeasts and other replication-related activities among vertebrates (Livengood et al 2002). And third, the TERT proteins of the telomerase locate specific domains and these domains are referred to as motif T. This motif T is vital for RNA binding (Friedman Cech 1999; Kelleher et al 2002). The specific actions of the two components of the telomerase are vital towards the determining its applications. Current and Potential Applications of Telomerase There have been several misunderstandings about the application of telomerase in the field of biotechnology. The most popular false notion about telomerase is that it is the fountain of youth. Telomerase does not make a person stay young forever. What the telomerase can do is to support the replication of the chromosome and then, after many years, allow the state of senescence. It must be remembered that the telomerase only act upon the tips of the chromosomes and not on the lifestyle of a person. This implies that if a person decides to live a dangerous or unhealthy lifestyle, neither his telomerase nor any modification on this enzyme will ever prevent his early death. The telomerase does not immortalize any organism. But this does not mean that the telomerase has no significant application. One of the most significant applications of telomerase is in the field of oncology. That is, the telomerase has been found to act abnormally during the replication of cancer cells. In normal cells, the action of telomerase ceases right after the chromosomal replication. But in cancer cells, the telomerase remains active. Scientists assume that there must be some structural difference between the telomerase of normal cells and that of cancer cells. If the structural difference is found, it might be possible for molecular biologists to seek out cancerous cells by seeking the telomerase only. Then, a person who has cancer at the early stages can be diagnosed immediately and can utilize cancer therapeutic treatments that involve the inhibition of the abnormal telomerase (Shay et al 2001). Conclusion The discovery of the telomerase is one of the most significant events in science history. It can be considered as vital as the discovery of the double helix structure of the DNA. This is because this enzyme allows the accurate and regulated replication of the linear chromosomes of eukaryotes. But, just as the discovery of the enzyme was challenging, the establishment of its properties and functions are equally difficult to carry out. Yet, molecular biologists persevere and came up with interesting possible applications of telomerase. Bibliography Blackburn, EH, Lin, J, Ly, H, Hussain, A, Abraham, M, Pearl, S, Tzfati, Y, Parslow, TG 2004, ‘A universal telomerase RNA core structure includes structured motifs required for binding the telomerase reverse transcriptase protein’ Proceedings of the National Academy of Sciences of the United States of America, vol. 101, no. 41, October, pp. 14713-14718, National Academy of Sciences pnas. 0405879101 viewed 10 September 2007, http://www. pnas. org/cgi/content/abstract/101/41/14713. Brown, J 2005, ‘What the Heck is an Enzyme’ Bugs in the News, viewed 10 September 2007, http://people. ku. edu/~jbrown/whatheck. html. Chappell, AS, Lundblad, V 2004, ‘Structural Elements Required for Association of the Saccharomyces cerevisiae Telomerase RNA with the Est2 Reverse Transcriptase’ Molecular Cell Biology, 24: 7720-7736. Chen, JL, Blasco, MA, Greider, CW 2000, ‘Secondary structure of vertebrate telomerase RNA’ Cell, 100: 503-514. Chen, JL, Greider, CW 2004, ‘An emerging consensus for telomerase RNA structure’ Proceedings of the National Academy of Sciences of the United States of America, vol. 101, no. 41, October, pp. 14683-14684, National Academy of Sciences pnas. 0406204101 viewed 10 September 2007, http://www. pnas. org/cgi/content/full/101/41/14683. Dandjinou, At, Levesque, N, Larose, S, Lucier, JF, Abou-Elela, S, Wellinger RJ 2004, ‘A phylogenetically based secondary structure for the yeast telomerase RNA’ Current Biology, 14: 1148-1158. Friedman, KL, Cech, TR 1999, ‘Essential functions of amino-terminal domains in the yeast telomerase catalytic subunit revealed by selection for viable mutants’ Genes Dev. 13: 2863–2874. Kelleher, C, Teixeira, MT, Forstemann, K, Lingner, J 2002, ‘Telomerase: biochemical considerations for enzyme and substrate’ Trends Biochem. Sci. 27: 572–579. Lai, CK, Miller, MC, Collins, K 2002, ‘Template boundary definition in Tetrahymena telomerase’ Genes Development, 16: 415–420. Lin, J, Ly, H, Hussain, A, Abraham, M, Pearl, S, Tzfati, Y, Parslow, TG, Blackburn, EH 2004, A universal telomerase RNA core structure includes structured motifs required for binding the telomerase reverse transcriptase protein’ Proceedings of the National Academy of Sciences of the United States of America, vol. 101, no. 41, October, pp. 14713-14718 Livengood, AJ, Zaug, AJ, Cech, TR 2002, ‘Essential Regions of Saccharomyces cerevisiae Telomerase RNA: Separate Elements for Est1p and Est2p Interaction’ Mol. Cell. Biol. 22: 2366–2374 Peterson, SE, Stellwagen, AE, Diede, SJ, Singer, MS, Haimberger, ZW, Johnson, CO, Tzoneva, M. Gottschling, DE 2001, ‘The function of a stem-loop in telomerase RNA is linked to the DNA repair protein Ku’ Nat. Genet. 27: 64–67. Shay, J, Zou, Y, Hiyama, E, Woodring, EW 2001, ‘Telomerase and cancer’ Human Molecular Genetics, vol. 10, no. 7, pp. 677-685. Skloot, R 2001, ‘The Marvels of Telomerase’ Hopkins Medical News, winter 2001, viewed 10 September 2007, http://www. hopkinsmedicine. org/hmn/W01/top. html. Tzfati, Y, Knight, Z, Roy, J, Blackburn, E H 2003, A novel pseudoknot element is essential for the action of a yeast telomerase, Genes Development 17: 1779–1788. Vermolen, BJ, Garini, Y, Mai, S, Mougey, V, Fest, T, Chuang, TCY, Chuang, AYC, Wark, L, Young, IT 2005, ‘Characterizing the Three-Dimensional Organization of Telomeres’ Cytometry, 67A: 144-150. Zapulla, DC, Cech, TR 2004, ‘Yeast telomerase RNA: A flexible scaffold for protein subunits’ Proceedings of the National Academy of Sciences of the United States of America, vol.