Laser surgery
Lasers (The word laser is an acronym for light amplification by stimulated emission of radiation.) lasers were first introduced in 1960, The first successfully optical laser constructed by Maiman (1960), was a ruby crystal surrounded by a helicoilal flash tube enclosed within a polished aluminum cylindrical cavity cooled by forced air. The ruby cylinder forms a Fabry-Perot cavity by optically polishing the ends to be parallel to within a third of a wavelength of light. Each end was coated with evaporated silver; one end was made less reflective to allow some radiation to escape as a beam was produced. Initially the laser was named the invention looking for a job. Photo-pumped by a fast discharge flash-lamp, the first ruby lasers operated in pulsed mode for reasons of heat dissipation and the need for high pumping powers. Nelson and Boyle (1962) constructed a continuous lasing ruby by replacing the flash lamp with an arc lamp.(1) Today lasers are much like those of the early ones and they are widely used in many fields, their uses are wide spread, From fusion physics to the DVD player these are common places where lasers are used. Medicine and surgery are no exceptions from skin resurfacing to eye surgery to correct vision. With the development of lasers Physicians have been able to provide treatment for a large number of medical disorders. Medical lasers have made it possible to treat conditions, which were previously untreatable or difficult to treat. To make the most of the laser technology physicians must maintain a up to date understanding of laser systems and conditions for which each can be applied .To achieve these goals the basic terminology and fundamentals of laser-tissue interaction is needed.
Before we can learn about lasers we need to know a little about light, because that is essentially what a laser is made of. First the speed of light is 3.00*10to the 8th meter per second .The American physicist Albert Michelson found a ratio 1.33 for the speed of light c in a vacuum to the lights speed v in water. This value is equal to the index of refraction n thus n=c/v gives us a way to predict the speed of light in any material once we know its index refraction.(2) Lasers produce a intense beam of bright light that travels in one direction. And a laser has the unique ability to produce one specific color or wave length of light which can be varied in its intensity and pulse.
...d in acts to try and please God or whom ever they wish to gain forgiveness from. Most people naturally tie depression to death; people in this stage will experience sadness, regret, and fear of what is to come. The final stage is acceptance, this stage is very straightforward, it is in this stage that the individual realizes their fate and are okay with it and what they have done. (Elisabeth Kübler-Ross -Five Stages of Grief, Business Balls). Dimmesdale is a very, very troubled man to say the least. Throughout The Scarlet Letter Dimmesdale is shown going through the five stages of grief, he lets his sin rule and control his life and lets it ultimately lead to his demise.
In Nathaniel Hawthorne’s The Scarlet Letter, the guilt bestowed upon two passionate lovers committing adultery reveals the corrupt and over-radical beliefs of a strict Puritanical society. Hester Prynne and Arthur Dimmesdale face life-changing consequences after submitting to their emotions and committing sin. The narrator’s forgiving tone presents the society as being very strict in living by their social and religious codes. The administrative, or authoritarian, imagery conjured up by various scenarios with the scaffold, magistrates, and the mayor in hid castle supports the tense mood as Hester and Dimmesdale try to mysteriously elude the laws of their community. Hawthorne employs allegory to the names of many characters in the novel to suggest their vulnerable personalities as they, in many cases, become shaped by the Puritanical views. Most importantly, the abundance of symbolism, such as the scarlet letter “A” itself, hammers home the effects of the Puritanical moral values on the characters in the novel.
The nature of memory can be explained as a set of stages that are necessary but not sufficient for memory to have taken place. These involve "input" -registering or encoding information, where a memory trace is formed from translating the sensory data, "storage" which is either temporary or permanent and "output" which involves retrieval - memories would be useless unless they could be retrieved. It is these stages that form the fundamental characteristics of the process of memory and in order for this to occur it is necessary for the data to become engaged in the memory structure. Memory structure can be separated into three distinct categories, sensory memory (input store) where the sensory data remains unchanged in the mind fo...
In 793 A.D., a small tidal island off the northeast coast of England known as Lindisfarne was home to the first Viking raid in history. The monastery on the island was a well-known holy place at the time. Its priests were slaughtered and the monastery was plundered of all its treasures. Shortly after the attack, leading Christian figure Alcuin deemed it the worst atrocity Britain had ever witnessed by the pagans. He did not know that this raid would become the first of many and would indicate the beginning of a time known as the Viking Age. In his book The Vikings: A History, Robert Ferguson discusses this age in great detail and analyzes its importance to Western Civilization.
The Viking community was a diverse group of people, from Kings, Jarls, and great warriors to poets and scholars. Extended famili...
Most Vikings lived in Scandinavian countries such as Denmark, Norway and Sweden. But also started settling in, in other countries such as Iceland; the Vikings discovered Iceland in the ninth century, a country with volcanoes and lots of snow. They also settled in Russia, The Netherlands, Germany, France, Normandy, England, Scotland, Iceland and Canada. Normandy was one of the largest and main settlements for the Vikings and was founded by Rollo, a Viking leader after conquering England in 1066. In the tenth century the Vikings founded the first European settlement in Greenland. The Vikings also destroyed France in 855. Just recently, archeologists and historians discovered that from 989 to 1020 Vikings lived in Newfoundland Canada and had huts for different activities such as weaving, ironworking and ship repair. This is the first evidence of Viking existence in North America. Since the Vikings attacked and plundered so many countries, they had the option of settling into those countries.
Without an honorable reputation a person is not worthy of respect from others in their society. In Nathaniel Hawthorne’s novel, The Scarlet Letter, the struggle to shake off the past is an underlying theme throughout the novel. Characters in this novel go through their lives struggling with trying to cope with the guilt and shame associated with actions that lost them their honorable reputation. Particularly, Hawthorne shows the lasting effect that sin and guilt has on two of the main characters in the book: Hester Prynne and Reverend Dimmesdale.
The author of The Scarlet Letter, Nathaniel Hawthorne, expressed ideas of love, passion, shame, and punishment throughout his 1800s based novel. Due to the fact that this novel was based in a Puritan time period, it brought many mental and sometimes physical difficulties for the main character, Hester Prynne. The Puritans solely believed in God and all of his rules. With that said, the author decided to illustrate the drama of Hester Prynne and Arthur Dimmesdale’s adultery in order to describe the change in Hester’s attitude. Because of the many events, adversities and struggles, Hester had a complete change in attitude from shame and embarrassment to love, proudness and satisfaction.
However, the era is better marked as coming to a conclusion when William the Conqueror (also a descendant of Vikings) successfully took the English throne and became the first Norman king of England in the same year of 1066 AD at the Battle of Hastings.
In short, Arif Alickaj was one of the many, many Albanian heroes of the Holocaust. Thanks to the besa code and his job, he was able to create fake identity papers and helped many Jews pass as Muslims. He was risking more than just his job while doing this-he was risking his life. After World War II ended, Arif Alickaj lived out a long life and he was dedicated to following the besa code, like so many other Albanian Muslims. Arif Alickaj could have lost everything he had, but he went ahead and risked it. Because of this and his willingness to help keep the Jews safe from the Nazis, Arif Alickaj truly deserves to be called a hero of the Holocaust.
The Reverend Dimmesdale was another character that demonstrated the effects of sin. He committed the same offense that Hester committed, adultery. The difference between Dimmesdale and Hester was that Dimmesdale was not publicly punished for his crime while Hester was. Because of this, Dimmesdale felt extremely guilty. This feeling of guilt was so atrocious that it mentally and physically withered Dimmesdale, as he felt a very strong need to repent and cleanse his soul.
Researchers of one study compared the use of reward with the use of punishment in teaching tasks to young adults. The findings suggested that rewards were more effective in learning enhancement, whereas punishment only taught motor learning of the task (Wachter, Lungu, Liu, Willingham, & Ashe, 2009). This finding illustrates that it would be more effective to implement a system of positive reinforcement in attempting to get my brother to do his chores, rather than implementing a punishment procedure. In addition, withholding positive reinforcement can serve as its own form of negative punishment to an individual, and that withholding positive reinforcement is at least as effective, if not more effective, than simply using punishment. One pediatric psychologist pointed out that, when he substituted punishment procedures with withholding positive reinforcement, the classes he had worked with engaged in less problem behaviors than before (Brown, 2003). As such, it is important that I do not hand out certain reinforcers to my brother when he does not do his chores as frequently or as satisfactorily as requested by my parents and me. After reviewing the research on this topic, it is vital that the intervention I enact contains an element of positive reinforcement, and that I need to reduce his cell phone usage so that he becomes active in completing his assigned chores at a satisfactory level and frequency. Additionally, it has been found that token economies are highly effective in households where someone refuses to do chores. In one study, consisting of 5 graduate students who had previously refused to do chores in their houses, a token economy was enacted. After the system had been removed for two weeks, the individuals were still doing the chores as they had been doing when the
As you can see lasers are a very useful and important tool which is why I have
Prior research into the structure of memory have suggested that memory is comprised up from three separate stores each performing a specific and relatively inflexible function (in Passer, Smith, Holt, Bremner, Sutherland, & Vliek, 2009). That is the multi-store model, developed by Atkinson & Shiffrin (1968 in Passer et al., 2009) who claim a sensory memory store, short-term memory store (STM) and a long-term memory store (LTM) (in Passer et al., 2009). Although to some, the multi store model provided an adequate explanation of memory processes, it was regarded as being too simplistic since short-term and long- term memories were far more complicated than originally thought (in Craik & Lockhart, 1972). In essence, the multi-store model stresses the importance of rehearsal to long term memory. While rehearsal is crucial as a means of transferring information from the STM to the LTM, this is not necessarily always the case (in Atkinson & Shiffrin, 1968 in Passer et al., 2009). To this, sceptics challenged the idea of information being transferred from the STM to the LTM by active rehearsal since subsequent research has indicated that information had the potential to be stored in the LTM without it being actively rehearsed (in Atkinson & Shiffrin, 1968). In response to the difficulties and weaknesses presented in the multi-store model, an alternative model attempting to explain memory processes in a more precise manner was developed by Craik & Lockhart (1972 in Craik & Lockhart, 1972). Their theory of levels of processing proposes that different methods of encoding information into the memory will subsequently have an effect on recollection of information (in Craik & Lockhart, 1972). According to the levels of process...
Refraction is a process that occurs when light travels between media of different optical density. Light travels at a speed of roughly 3.0 × 108ms-1 in a vacuum. A vacuum has a refractive index n=1.00. The speed at which the light is travelling will decrease as it moves into differently optically