Theories of Colour Vision

Theories of Colour Vision Kishan Lakhani How does colour vision work? It is difficult to imagine a world without colour perception as it is constantly in action by a whole spectrum of living organisms and for a range of purposes, it â€Å"not only allows us to detect objects that might otherwise be obscured by their surroundings; it also helps us to recognize and identify things we can see easily† (Goldstein, 2000, p.203), thus making it an essential component of vision. Colour dictates survival in many environments; the artic fox boasts a white pelt allowing effective camouflage over its prey and a significant factor in its ability to hunt (Sekuler Blake, 2006). I will explore the mechanisms that are said to explain colour vision at the photoreceptor level and beyond, but first of all we must understand what colour actually is. The electromagnetic spectrum ranges from cosmic rays to radio waves, as wavelength increases. Between UV and Infrared lies a strip, visible light, this is what we are interested in with regard to colour (Snowden et al., 2006). Colour arises when light rays from this visible spectrum (390nm-750nm) are reflected off objects and into our eyes. Differing wavelengths of light from this spectrum subsequently determine the colour perceived, as short wavelengths produce the colour violet (350nm), medium and long wavelengths produce green and red respectively. Sir Isaac Newton famously wrote â€Å"The rays to speak properly are not coloured. In them there is nothing else than a certain Power and Disposition to stir up a Sensation of this or that colour† (Sekuler Blake, 2006, p.236) So colour doesn’t really exist in the physical world at all, it is our own psychology that creates the concept of colour. Semi Zeki (1983) refined Newton’s words further saying that colour vis ion is a â€Å"property of the brain, not the world outside.†( Sekuler Blake, 2006, p.236) Hence we can sum up that colour vision lies in the eyes and brain – and not in the physics of light itself (Anderson 2012). So to answer the question ‘How does colour vision work’ we must explore the visual systems of the organisms further. Figure 1 The Electromagnetic spectrum (2012), Diagram showing the visible spectrum within the electromagnetic spectrum Photoreceptors are light sensitive cells found at the back of the eye in the retina. They contain visual pigments that absorb photons of light and convert this light energy into chemical energy, this process is called phototransduction. Within the pigment is a protein which determines the wavelength of light absorbed by the pigment and also a chromophore which is responsible for absorbing photons of light. (Wolfe et al., 2009) There are 2 types of photoreceptors, rods and cones. Cones are mainly concentrated in the fovea in the centre of the retina whereas Rods are completely absent in the fovea and more prevalent in the periphery of the retina (Snowdon et al,. 2006). Rods are adapted so they can operate in low light levels due to spatial pooling allowing scoptic vision, whilst sacrificing visual acuity. They contain just one pigment rhodopsin – denying colour vision due to the univariance principle. Cones however contain 3 photo pigments, which are sensitive to various wavele ngths of light and can therefore let us see colour. In comparison to the physical description of light, colour is much easier to describe as it is experienced psychologically not physically – such is the nature of light. It can be specified by just three values; hue, saturation and lightness.(Palmer, 1999) This is very important with reference to colour vision as it implies that many different lights will produce the same colour experience (Palmer, 1999). The three perceptual dimensions of colour can be summarised in what is known as the colour spindle. Hue is referred to as â€Å"the chromatic aspect of light† (Wolfe et al., 2009) and is dictated by its wavelength. Saturation corresponds purity and how vivid the colour is (Palmer 1999), and brightness involves the intensity of the colour (physically). The Young/Helmhotz trichromatic theory of colour vision works on the photoreceptor level, and ultimately was sprouted through the results of Helmhotz’s colour matching experiment. Observers were allowed to vary the intensities of 3 primary lights and mix them (in a comparison field) to match the colour of a single wavelength in a test field. They had to find a psychological match between the mixture of primary lights and the test light, simply by varying the intensities of the primary lights. This match is known as a metameric one, as the light in the comparison field is physically different yet psychologically identical to that in the test field. Results showed that by varying intensities in the comparison field, the observer could find a metameric match using just three primary lights. Dichromatic observers were unable to find matches for every colour in the test field. In summary, â€Å"with 3 primaries, you can get any combination of responses in the 3 cone types, so you can match the appearance of any test light.† (Anderson 2012) It is therefore clear to us that colour vision heavily relies on three different receptor mechanisms or cone photopigments, each with different spectral sensitivities (Goldstein, 2010). This is the basis of the trichromatic theory I will now elaborate on. Monochromats possess only one type of pigment in their cones. In this case, the ability to see colour is not possible. The same chain of events is initiated in the visual receptor despite there being a variety of wavelengths in the light absorbed by the pigment. The receptors response conveys information about how much light has been absorbed, but this response provides no information about the wavelength of this absorbed light. (Sekuler Blake, 2006) It is therefore impossible to discriminate wavelength when there is only one photopignment, which has uniform spectral sensitivity. The response could have altered due to a change in wavelength or light intensity, and monochromats are none the wiser – this is known as the principle of univariance. This situation is not unique to monochromats, as in low light levels rods are the only photoreceptors in action. They have one photopigment, rhodopsin resulting in the same dilemma. Consequently we â€Å"disregard the wavelength inform ation and see an image that appears in shades of grey† (Snowden et al., 2006) explaining why we can’t monochromats can’t see colour and why none of us have colour vision in low light levels. Dichromats possess two photopigments, which is very useful in terms of colour vision. The two pigment types have different absorption spectra, extracting some usable wavelength information about light (Sekuler Blake, 2006) It is now possible to separate and disentangle wavelength and intensity, allowing colour to be visible to a certain extent. Certain wavelengths are confused and constitute failures of discrimination (Sekuler Blake, 2006). A key reason that leads to the idea humans aren’t dichromats revolves around what is known as the neutral point. All dichromats possess this neutral point in which a single wavelength is always confused, and â€Å"the existence of a single neutral point is the hallmark of a two-pigment eye.† (Sekuler Blake, 2006, p.249) As humans do not show any traits of having the neutral point, there is a strong belief that humans have more than two cone photopigments. Trichromats hold three cone photopigments, enabling total discrimination of wavelengths throughout the visible spectrum. Trichromacy also ties in with Helmhotz’s colour matching experiment, indicating three not two photoreceptors are required for complete colour vision across the entire visible spectrum. The three pigments are most sensitive to light of a particular wavelength – approximately 430, 530 and 560 nanometres respectively. (Sekuler Blake, 2006) Figure 4 shows the each cone pigment absorbs a very wide range of wavelengths. So between 400nm and 650nm there are at least two types of cone photopigments absorbing light. In the region of 475nm, all three types of pigments are affected and stimulated. (Sekuler Blake, 2006) Hence we can conclude that the absorbance range is tremendously increased with three photopigments, and as light is reflected onto the retina every wavelength of light in the visible spectrum can be perceived in the form of colours by our brain. Trichromatic theory may explain how the existence of just three cone photopigments allows colour matching for any wavelength of light in the visible spectrum, using just three primary lights. However, it still leaves many unanswered questions when it comes to having a full understanding of how colour vision works – as Hering highlighted. Negative afterimages, the visibility of four psychologically pure hues (blue, red, green and yellow) and the absence of complementary hues such as blueish – yellow all indicate that trichromatic theory alone is inadequate in explaining how colour vision works. Hering made an important discovery with regard to afterimages. If we stare at the black dot in Figure 5 for around 30 seconds, and then look at a blank piece of paper we notice the colour of each square changes. The green changes to red and red to green, whilst the blue changes to yellow and the yellow to blue. Based on results like these, Hering proposed the concept that red and green are paired and blue and yellow are likewise paired. (Goldstein, 2010) An experiment where observers were shown patches of colour, and then asked to estimate the ratios of blue, green, red and yellow from each patch they received. Results showed that observers very rarely saw blue and yellow, or red and green together. (Abraham Gordon, 1994 cited in Goldstein, 2010) Sekuler and Blake (2006, p.255) also support this view that these complementary hues do not coexist, as â€Å"an object never appears both blue and yellow at the same time.† Hurvich and Jameson’s hue cancellation experiment st rengthens the case further, as any redness was eliminated when a green light was added to the red light. Hering also observed that those who are colour blind to red, are also colour blind to green; which ultimately led him to declare the opponent-process theory of colour vision. (Goldstein, 2010) So we can deduce from this evidence that blue is paired with yellow and red with green; the basis of the opponent-process theory. The opponent-process theory of colour vision follows the trichromatic theory, rather than replacing it, the two work hand in hand to explain how colour vision works. In fact it is the responses from the cones of the retina that form the basis of the opponent channels. (Anderson 2012) There are three opponent channels, two chromatic and one achromatic, and are formed by combining the responses from the three cone types. (Sekuler Blake, 2006) Figure 6 displays the red-green chromatic channel is comprised from the outputs of the M and L cones. It is also known as the M – L channel, as it signals the difference between the outputs of the M cones and of the L cones. (Sekuler Blake, 2006) The second chromatic channel is the blue-yellow channel, and it represents the difference between the S cone outputs and the sum of the M and L cone outputs. (Sekuler Blake, 2006) It is therefore also referred to as the S – (M + L) channel. The achromatic channel is known as the luminance channel, and combines the output of the M and L cones so we can also label it the M + L channel. The activity in this luminance channel hinges on the sum of excitation of both M and L cones (Sekuler Blake, 2006). This addition can lead determine an object’s visibility, â€Å"The shape of the photopic sensitivity curve (closely related to visibility) can be predicted by taking a sum of M and L cone responses.† (Smith and Porkorny, 1975 cited in Werner et al., 1984). Russel DeValois was responsible for the finding of opponent neurons in the retina and lateral geniculate nucleus (LGN), which could provide physiological evidence to back up Hering’s propositions. (Goldstein, 2010) The LGN is the station responsible for receiving input from the retina and transmitting it to the visual cortex. Devalois conducted experiments on LGN cells of monkeys (who have the same trichromatic vision as ours), and discovered opponent cells which behaved as if subtracting outputs from different cones and also nonopponent cells which behaved as if adding outputs from different cones. Devalois discovered opponent cells reproduced an ON or OFF response determined by the wavelength of light. (Sekuler Blake, 2006) This can explain the first chromatic channel Hering proposed (M – L) channel. Long wavelength cone excitation results in a positive or ON response, whilst medium wavelength cone excitation results in a negative or OFF response. Hence if the net re sponse is positive then a red colour is visualised (long wavelength of light), and similarly a blue colour is perceived if the net response is negative. This supports Hering’s initial observation that the hues red and green cannot coexist. Opponent cells were also responsible in explaining the S – (M + L) channel. Short wavelength cone excitation results in a positive or ON response, whilst wavelengths around 580nm (M+L) cone excitation results in a negative or OFF response. Further findings included the fact that nonopponent ON cells produced ON responses for every wavelength, although some wavelengths produced stronger responses than others and OFF cells produced OFF responses for every wavelength again with varying strengths. It is these nonopponent cells which form the achromatic channel outlined by Hering. (Sekuler Blake, 2006) All in all, colour vision begins at the photoreceptor level as explained by trichromatic theory. The outputs of the three cone photopigments have been redistributed into the achromatic and chromatic channels at the LGN, as trichromacy progresses to opponent-process theory. Palmer (1999) concludes by describing the dual process theory; in which the products from the trichromatic stage are used as the inputs for the secondary opponent-process stage. As we venture from the LGN, further into the visual system, the information is perceived by the visual cortex of the brain facilitating us with colour vision. Bibliography Anderson, S (2012). Colour vision, Vision and visual perception, Optometry. Aston University Dimitri Poumidis, (2008), Spectral Sensetivities [ONLINE]. Available at: http://www.gravurexchange.com/gravurezine/0805-ezine/ploumidis.htm [Accessed 25 January 13]. Goldstein, E. B. (2010). Sensation and perception (8th ed.) Chapter 9. Wadsworth Cengage Learning Joshua Stevens, Jennifer M. Smith, and Raechel A. Bianchetti , (2012), The Electromagnetic Spectrum [ONLINE]. Available at: https://www.e-education.psu.edu/geog160/node/1958 [Accessed 03 January 13]. Marc green, (2004), Opponent process theory [ONLINE]. Available at: http://www.visualexpert.com/FAQ/Part1/cfaqPart1.html [Accessed 09 February 13].Paul Schils , (2012), Chromatic adaptation [ONLINE]. Available at: http://www.color-theory-phenomena.nl/12.00.htm [Accessed 08 February 13]. Palmer, S. E. (1999). Vision science: photons to phenomenology, Chapter3. Massachusetts Institute of Technology Sekuler R. Blake R. (2005). Perception (5th ed.) Chapter 2. McGraw-Hill Sekuler R. Blake R. (2005). Perception (5th ed.) Chapter 7. McGraw-Hill Snowden R., Thompson P. Troscianko T. (2006). Basic Vision, Chapter 1. Oxford University Press Snowden R., Thompson P. Troscianko T. (2006). Basic Vision, Chapter 5. Oxford University Press Tom Jewett, (2009), Hue, Saturation, Brightness [ONLINE]. Available at: http://www.tomjewett.com/colors/hsb.html [Accessed 10 January 13]. Wolfe, J.M., Kleunder, K.R., Levi D.M., et al (2009). Sensation and perception (2nd ed.), Chapter 5. Sinauer Associates Inc

Comparing Obsession in Mary Shelley’s Frankenstein and Aldous Huxley’s

Comparing Obsession in Mary Shelley’s Frankenstein and Aldous Huxley’s After Many A Summer Dies the Swan Authors leave fingerprints on the works they write. Underneath the story, hidden amidst the words, lies a worldview, a concept of humanity, a message. Mary Shelley’s Frankenstein is an entertaining story meant to give the reader goose bumps late at night, but the telling of the story also reveals Shelley’s concept about the basic fabric of human nature. In the same way Aldous Huxley in After Many A Summer Dies the Swan weaves a tale that is part story and part commentary on how humans interact and think and self- destruct. In Frankenstein, Mary Shelley portrays obsession as an anomalous aspect of human behavior resulting when people move away from their basically good nature, while Aldous Huxley portrays obsession as the most intrinsic of all human qualities. This paper will contrast the basic views presented in each book about the origin of obsession and its relation to human nature, giving examples of how the authors’ views are embodied in their characters. In the novel Frankenstein, Mary Shelley presents a view of human nature that is largely positive so long as it does not wander into the dangerous realm of obsession. She speaks of human endeavors and discoveries as being valuable and good. The young Victor is enchanted by scientists who have â€Å"performed miracles† by â€Å"penetrating the recesses of nature† (45). The discovery and contemplation of the natural world is a means by which characters find serenity and calm, and thus come in tune with the beauty of their humanity. In the midst of the sublime wilderness, even Victor contemplates â€Å"divine ideals of liberty and self-sacrifice† (1... ...nts human nature as basically good aside from the selfish obsession perpetuated by withdrawal from normal society and human behavior. Huxley offers a bleaker view, portraying self- obsession as an innate quality ensnaring all of his characters unless they are freed to transcend their humanity and seek another level of consciousness. If Shelley and Huxley were here today, debating the merits of their stance, Shelley may might utter the words of Pete Boone, â€Å"I suppose I’ve been too optimistic.† And Huxley, adjusting his thick glasses, might reply as Propter did, â€Å"Too optimistic in certain directions, and at the same time too pessimistic in others† (188). Works Cited Huxley, Aldous. After Many a Summer Dies the Swan. Mattituck, New York: American Reprint Company, 1976. Shelley, Mary. Frankenstein. New York: Barnes and Noble Classics. 2003.

The Buchanan Report And The Monderman Thesis

The statement is false. This is a tricky question! Although the Buchanan Report and the Monderman thesis do offer visions of how to manage traffic they also offer us two competing visions of social order. The Buchanan Report is underpinned by a social order which privileges the segregation of humans and motors through an array of measures in urban design and the regulation of the conduct of both drivers and pedestrians. This social order emphasises the value of a social environment delivering the conditions for individual mobility and car acquisition as a valued mark of success. The Monderman thesis stresses a social order where involvement and cooperation emerges from an individual capable of negotiating with others a shared use of public space. In this shared space approach, people are not segregated from traffic. You're right. Although Goffman's view of the centrality of interaction is visible in Monderman's approach to negotiating ‘shared space', Chapter 7 argues that, as Foucault shows, social order tends to be specified by experts within particular historical discursive frameworks. Although both Buchanan and Monderman were important in their own right, their ideas were developed and taken up within particular contexts that ‘authorised' their development (made their ideas seems appropriate and fitting to the needs of the time). Foucault claims that expert discourses, established by those with power and authority, are often disputed by competing expert discourses. Buchanan's ideas have dominated for a long period. Monderman's are perhaps gathering force and challenging those of centralised planning and direction. Foucault's view of how the authority to order social life is bound up with scientific knowledge is demonstrated in the discourses and practices of both Buchanan and Monderman.

Facts About the Order Cetacea

Facts About the Order Cetacea The Order Cetacea is the group of marine mammals that includes the cetaceans - the whales, dolphins and porpoises. Description There are 86 species of cetaceans, and these are divided into two suborders - the mysticetes (baleen whales, 14 species) and odontocetes (toothed whales, 72 species). Cetaceans range in size from just a few feet long to over 100 feet long. Unlike fish, which swim by moving their heads from side-to-side to swing their tail, cetaceans propel themselves by moving their tail in a smooth, up-and-down motion. Some cetaceans, such as the Dalls porpoise and the orca (killer whale) can swim faster than 30 miles per hour. Cetaceans Are Mammals Cetaceans are mammals, which means they are endothermic (commonly called warm-blooded) and their internal body temperature is about the same as a humans. They give birth to live young and breathe air through lungs just like we do. They even have hair. Classification Kingdom: AnimaliaPhylum: ChordataClass: MammaliaOrder: Cetacea Feeding Baleen and toothed whales have distinct feeding differences. Baleen whales use plates made of keratin to filter out large quantities of small fish, crustaceans or plankton from the sea water. Toothed whales often gather in pods and work cooperatively to feed. They prey on animals such as fish, cephalopods, and skates. Reproduction Cetaceans reproduce sexually, and females usually have one calf at a time. The gestation period for many cetacean species is about 1 year. Habitat and Distribution Cetaceans are found worldwide, from tropical to arctic waters. Some species, like the bottlenose dolphin may be found in coastal areas (e.g., southeastern U.S.), while others, like the sperm whale, may range far offshore to waters thousands of feet deep. Conservation Many cetacean species were decimated by whaling. Some, like the North Atlantic right whale, have been slow to recover. Many cetacean species are protected now - in the U.S., all marine mammals have protection under the Marine Mammal Protection Act. Other threats to cetaceans include entanglement in fishing gear or marine debris, ship collisions, pollution, and coastal development.

Importance of schedule and routine for Young children Essay Example

Importance of schedule and routine for Young children Essay Example Importance of schedule and routine for Young children Essay Importance of schedule and routine for Young children Essay The agenda and everyday constituents of planning can assist make a model of security for immature kids. Children who are provided with a predictable agenda and secure environment are more likely to experience confident about researching their universe . Through these geographic expeditions, kids strengthen their connexions to the people and environment around them ( Klein, 2002 ) . The format becomes familiar to them, and they welcome the periods of self-selected activities, group clip, out-of-door drama, resting, eating, and toileting. The constitution of trust that grows between instructor and parent is based on consistent day-to-day contact and the wellbeing of the kids. An Educational Program is a procedure by which pedagogues use Five Specific Principles that are cosmopolitan constructs accepted by professionals working with immature kids: All kids are alone. Child s parents are their primary pedagogues. Child learn though drama. A kid s whole being develops as one. Childs take larning into their ain custodies. These rules guide pedagogues in their Three Main Duties: Establishing a acquisition environment. Planning and conducting activities. Intervening democratically with kids, parents, and staff members. A Planing Play Experiences Why Do Early on Childhood Educators Plan Play Experiences? Supportive counsel from grownups is indispensable for traveling kids to higher degrees of development. To assist kids develop in their usage of drama as a vehicle for increasing nervous constructions. Why Plan -To aid kids pattern accomplishments they will necessitate subsequently in life. To estimate a kid s developmental advancement A When kids are engaged in an activity, all countries of their development ; Physical, social-emotional, cognitive and linguistic communication are being stimulated. Any growing in one dimension triggers growing in others. It is of import for pedagogues to acknowledge all countries of development and to be after intercession, environments, and activities throughout the twenty-four hours that foster overall development of the kid. Because the kid s whole being develops as one: Design an environment that fosters all countries of development ( physical, social-emotional, cognitive and linguistic communication ) . Provide assorted stuffs with the aim of furthering all countries of development. A Because the kid s whole being develops as one: Establish a day-to-day and hebdomadal modus operandi that meets the developmental demands of kids. Observe kids to detect their abilities and endowments in all countries of development, and program activities that build on these. Plan state of affairss and play activities that foster the development of the whole kid A Because the kid s whole being develops as one: Record observations about the kids. Usher kids in productive ways so that, they may profit from all larning chances. Talk with kids about their drama. Keep ambitious kids. Collaborate with parents and co-workers. A Children Take Learning into Their ain Handss All kids already possess the seeds that will let them to develop to their full potency. Educators do nt make the acquisition for the kids, but they H2O the seed of acquisition by supplying age-appropriate challenges that reinforce the kids s abilities and construct on them. Educators open the manner by promoting kids to do picks, observe, experiment, explore, interact, and be independent. We empower kids when we allow them to develop their ain ideas, feelings, and organic structures, and back up them in pass oning their thoughts, doing links, being funny, and interacting actively with the universe around them. When we provide kids with chances particularly created for them, they become active scholars and lief take part in the procedure. Because kids take larning into their ain custodies: Establish clearly-defined, good -equipped larning Centres in rumpus rooms. Ensure that the acquisition environment is at kids s degree and to the full accessible. Arrange stuffs to promote liberty, decision-making and active engagement. Label shelves and transparent bins with images that show where stuff belong. A Because kids take larning into their ain custodies: Allow kids to take activities and stuffs harmonizing to their involvements. Offer open-ended activities. Plan activities that foster success. Use rumpus room direction tools ( planning boards, occupation boards ) . Plan activities that stimulate kids to detect their involvements and promote them to move upon them A A I. Time Agendas An Unstructured Timeline that explains what each clip slot will dwell of. Basic things to retrieve when making your clip agenda: Provide for jumping periods of quieter and more active experiences. Provide for indoor and out-of-door drama. Have sensible gait throughout the twenty-four hours. Have a balance between single ego selected learning experiences every bit good as little and big group activities. What should it include? Meeting the Needs of Children The agenda should supply for jumping periods of quieter and more active experiences. The agenda should supply for indoor and out-of-door drama. ( Include alternate activity periods for inclement conditions. ) The agenda should supply for a sensible gait throughout the twenty-four hours. The agenda should supply for a balance between single self-selected acquisition experiences, and engagement in the more structured small-group times. The agenda should supply for modus operandis. Meeting the Needs of Adults Adults need assortment merely as kids do. Adults need respite from being invariably with kids. The agenda must supply clip for health professionals to recognize and chew the fat with parents at the beginning and terminal of the twenty-four hours. A Sample Timetable 9:00 9:10 Good Morning single hullo s 9:10 9:30 Show and Tell 9:30 9:45 Exercise Time 9:45 10:00 Bathroom Time 10:00 10:30 Snack and Quiet Book Time 10:30 11:15 Centre Time 11:15 11:30 Math Activity 11:30 11:50 Language Time 12:00 12:30 Lunch 12:30 1:15 Deferral 1:15 2:00 Quiet Time ( Rest ) 2:00 2:30 Free Play 2:30 2:45 Story Time 2:45 3:00 Review of the Day s Events 3:00 3:15 Prepare for Home A As the kids arrive it is of import for early childhood educators/educational helpers to retrieve, that the kids s parents are their primary pedagogues. Educators play a truly of import function in kids s lives, because kids spend many hours each twenty-four hours in their attention. However, it is really of import that kid and household services workers neer forget that parents are the primary pedagogues of their kids. The pedagogue s function consists in supplying larning chances to kids that complement and reenforce the households values, attitudes and behaviors at place. Children will ever profit if parents and pedagogues are consistent in their educational attacks at place and at the Centre. This implies changeless communicating between parent and pedagogue. Parents should besides hold entree to the Centre s installations throughout their kid s twenty-four hours. It is of import that you greet each kid upon reaching. The parent should convey the kid to the rumpus room used for arrival clip, where kids of different age groups gather until most of the kids have arrived. It is of import that you, or the pedagogue nowadays, inquire the parent for any information that might hold an impact on the kid s twenty-four hours. Some kids will experience separation anxiousness and will shout as they see their parents leave ; it is of import to take clip to soothe these kids and to hold them concentrate on an activity or a plaything that is merriment. Typically, these kids shortly integrate into the group. A Engagement | Exploration | Application | Connection | Top created 12-Oct-2009 modified 12-Oct-2010 glossary right of first publication

Impact of Computers on Day-to-day Life Essay Example | Topics and Well Written Essays - 1000 words

Impact of Computers on Day-to-day Life - Essay Example Social networking is another area in which computers have changed peoples’ lifestyle. Many of the offline businesses were transformed to online businesses because of the abilities of computers in promoting e-businesses or e-commerce. Weather forecasting and global positioning systems are some of the other areas in which computers are used extensively nowadays. This paper analyses the impact of computers in day-to-day life. Business is one area, which gained a lot because of the introduction of computers. It should be noted that instant communication is made possible because of the introduction of computers and internet. Business always likes to have the exchange of information as quickly as possible in order to make sound decisions. Earlier, fax messages and telephonic conversations were used for business communications along with telephones. However, these technologies had many limitations in communicating the ideas properly between the stakeholders of business. The introduct ion of computers helped business people to present their ideas clearly to others. Computer controlled machinery is used a lot in many of the manufacturing units nowadays. This machinery has the ability to do provisioned work more efficiently than humans do. According to new figures released by the United States Department of Commerce, e-Commerce Sales accounted for 2.4% of all sales in the fourth quarter of 2005, up from 2.3% the previous quarter. Total fourth quarter e-commerce revenues came to a seasonally adjusted $22.94 billion. For all of 2005, e-commerce sales rose by 24.6% according to information from the U.S. Census Stats (Internet World Stats News) Earlier business activities were taking place only in the real world. Introduction of computers opened another channel for business in the virtual world. Many of the recent studies have shown that offline or virtual world business is going to surpass real world business in the near future. Computers have helped business people w ith another channel to market and provide their services. Education is another sector in which computers proved their worth. For effective transfer of knowledge from the teacher to students, computers are extensively used in classrooms at present. Computer assisted technologies are helping both the students and teachers to polish their ideas. For example, teachers can take notes from the internet before presenting a particular topic in the class. In the same way, exceptional students who are not satisfied with the classroom knowledge can look on the internet to get more knowledge. IPads and tablet PC’s are helping students to get rid of the inconvenience of carrying textbooks and notebooks to the classes. Teachers can assess the progress of the students with the help of computer software. In short, computers can help in the enhancement of quality of education. Social networking is the third segment in which computers are influencing people in their day-to-day life. The popula rity of Facebook, Google Plus, MySpace, Twitter etc clearly indicate the importance of computers in daily life. It should be noted that millions of people from all over the world are spending a substantial period of time in social networks nowadays. Apart from ordinary people, even business people, marketers, job seekers, etc are also interested in using social networks now. The concept of social networking would not be in place if the computer related technologies were not there. As mentioned

Cell biology &genetics - lab report Essay Example | Topics and Well Written Essays - 750 words

Cell biology &genetics - lab report - Essay Example The objective of this experiment is to observe the several stages of mitosis in an onion root cell through a light microscope. Onion root tips were prepared by washing in clean water then rinsing with distilled water. After this, a root tip section about 2mm in thickness was cut from the root tip using a sterilized scalpel; this was then placed on a glass slide with a drop of distilled water on it to avoid dehydration. Afterwards the root tip section was them fixed in Carnoy’s fluid inside a Bijou bottle for about 10 minutes. After fixing, the section was then transferred to a Petri dish containing distilled water where it was rinsed for approximately 2 minutes. After rinsing, the root tip section was then placed inside a bijou bottle containing 1 ml of 1M HCl and incubated at about 60ï‚ °C for about 5 minutes. The contents of the tube were then poured into a Petri dish and the root tip carefully picked out using forceps and transferred into another Bijou bottle containing aceto-orcein which was then left in a dark chamber for about 10 minutes. The bottle was then removed from the chamber and the root tip carefully removed using forceps and placed on a slide on which a drop of 45% acetic acid had been placed, this was then covered with a cover slip. By this time the root tip section was already well softened and stained; the tip was then squashed by slightly tapping on the cover slip with a pencil until it was evenly spread out under the cover slip as a pink mass. The glass slide with the root tip ready for observation on the microscope was then transferred to a light microscope and viewed at x400 magnification strength. Photographs of the cells undergoing mitosis were then taken and drawings made of the various stages of mitosis. It was observed in the experiment that the cell division process assumed all the four stages shown in the images above and that the staining clearly revealed the features of all the four stages it takes for a cell