Photoreceptor Damage: Causes and Possibilities :: Medical Medicine Papers

Photoreceptor Damage Causes and PossibilitiesOver 10,000,000 people around the world suffer from some sort of blindness or handicap due to photoreceptor damage. These cause can be caused by a number of afflictions, including retinitis pigmentosa, macular degeneration, and tumors. These illnesses vary in severity from being a mere hindrance to completely blinding the individual. Until recently, those modify were left without hope of a cure or even a treatment that would somewhat improve their vision. But over the last few years, some(prenominal) groups of scientists have been working on a partial cure in the form of neuroprostheses, artificial devices which argon inserted in the eye behind or on top of the damaged retinal argona. These photoreceptive chips, in theory, should provide information too the healthy neurons residing in the retina, substituting for the damaged photoreceptors.When we open our eyes, millions of tiny events occur that leave behind us to see. Our pupils auto matically constrict in accordance to the cloudless level, the variable lens bends and adjusts to fit the distance of what we are looking, and our photoreceptors receive information in accordance to the previous factors. (This is extremely simplified, but it will suffice for now.) Photoreceptors are tiny, specialized neurons located in the retina at the back of the eye. There are deuce types of photoreceptors, rods and cones. Each follow the same principles when light hits them they respond with a chemical reception using a substance known as rhodopsin. Once this reaction occurs a chain of events sends this message down a number of sophisticated and specialized neurons, eventually r from each oneing the brain and resulting in what we call sight.Rods (numbering one degree centigrade million or so in each eye) are primarily in the periphery of our visual field. They are extremely sensitive to light and are often tied together on a lower level to allow for greater sensitivity. Rods d o not see in with good courage and cannot differentiate colors.Cones (only five million or so exist) are mostly found on the center of the visual field, a place called the fovea. The words you are reading now are being processed by cones in the fovea. They operate in brighter light than rods and detect color (there are three types, each responding to a particular range of wavelengths). Cones do not pool their output and exist for resolution, not mere detection. The only drawback with the cone system is the amount of light saturation necessary to stimulate them and send their signal to the brain.

Modern Technology: Are We Too Dependent? Essay -- Internet Computers E

Modern Technology Are We Too Dependent?Internet and television, the twenty-first hundred has become consumed by these two relatively new forms of media. Devoting more time to one or both of these two creations than ever before, the Ameri roll in the hay public is speedily coming in from the outdoors and finding the technological marvels of the twenty-first century. Now more than ever television and internet are a major disassemble of peoples lives. The American Society is straying outside(a) from their roots as a nature loving community of interests and becoming a community dependent on technology.If comparing stories told by my bugger off about his childhood to those of mine, just one generation apart, drastic differences would be seen. Stories told by my father were of him and his brothers building forts in the woods, going camping for days with neighborhood friends and play in the woods all day until my grandmother would call him and his siblings in for dinner. My child hood was kind of a bit different. I also grew up spending a great bit of my childhood playing outside with my cousins and friends. Building tree houses, playing in the fall leaves, and all the different games kids play were just a few activities of our childhood days. However unlike my father who said he can remember when the first got a television when he was 6, I grew up with television. So I became curious. I wanted to know if most people my fathers age had the same experiences with televisions. In a survey I conducted to test the two generations. The 40+ age group (parents), and the 15-25 age group (children). The followers results were foundIn the 40+ age group, as a child50% watched an average of 5-6 hours per week50% watched an average of 7-8 hours per week... ...our direction (p. 163). He goes on to say that If were ever to recapture these fundamental kinds of information, its necessary to start by remembering just how divorced from the physical piece many of us have become (p.164). These passages from the essay give the results of survey great support. As time goes on society gets further and further away from their roots. Technology is spreading all across the world. Other countries of the world are devoting just as much time to these new technological marvels as Americans do. It is my depression that before it is all said and done every person in every city across the globe will own a television, and be connected to the internet truly making it a World Wide Web. ReferencesMcKibben, Bill. Daybreak. In A Forest of VoicesConversations in Ecology 2nd Edition(pp. 156-169). Mayfield make Company.

Lanston hughes comparison of two poems Essay -- essays research papers

In todays modern view, poetry has mother much than just paragraphs that rhyme at the end of each sentence. If the reader has an open mind and the ability to read in between the lines, they discover more than they have bargained for. Some poems might have stories of suffering or abuse, while others contain happy times and great joy. Regardless of what the poems contains, all poems display an expression. That truly moment when the writer begins his mental journey with that pen and paper is where all feelings are let out. As poetry is continues to be written, the reader begins to see patterns inside each poem. On the other hand, poems have nothing at all in common with one another. A good example of this is in devil poems by a famous writer by the name of Langston Hughes. A well-known writer that still gets credit today for pomes like Theme for position B and Let the Statesn be American Again. Theme for English B and Let American be American again share or so similar elements. T hese poems both written by Langston Hughes both explain about inequality. Theme for English B revolves around the separation of the black and white gentleman the differences within each race were segregation was at a high point. Let America be America again revolves around the concept that America is supposed to be the land of the free, but to another race or background its a total opposite. (I guess that being colored doesnt make me not like the other folks who are other races. - Theme for English B). ...