Contrary to popular belief, there is no ideal number when it comes to how much sleep a person needs each night. While eight hours is widely considered the benchmark for sleep, that number is more arbitrary than absolute. Researchers are discovering that how much sleep a person needs depends largely on the individual and his or her situation. Researchers are finding is that two factors have the biggest influence on how much sleep a person needs each night. One is a person's basal sleep need. Basal sleep need refers to how much sleep a person's body needs on a regular basis for optimal performance. This varies greatly depending on the individual. The second factor is a person's sleep debt. Sleep debt is the accumulation of sleep lost, whether it's sleep lost to sickness, environmental changes, or just overall poor sleeping habits. Some research has suggested that sleep debt can impact how a person feels for a long time, evenif that person has met their basal sleep need several nights in a row.
8.12.2008
8.04.2008
The colors of safety
A research study reveals that the color of a car, aesthetic factors aside, can help reduce accidents. When you buy a car, engine specifications, comfort, and safety play the main role in the selection, whereas the color is pushed to the background as a mere question of taste or fashion. But have you ever considered that the color of the car could be linked to safety?
According to a study carried out by the School of Public Health of the University of Auckland, New Zealand, that choice is very important when it comes to safety, because, for example, the risk of an accident in a silver-colored vehicle is five times lower than in a black one.
This study analyzed the effect of color and the risk of accident among over a thousand drivers and determined that brown, black, and green cars are involved in more accidents, whereas grey, red, and yellow ones are less accident-prone. This is because dark vehicles tend to "blend" into the surrounding area, rendering it more difficult to "pick them out" from the environment than light-colored cars.
In order to conduct this study, influential factors such as age, experience, speed, alcohol consumption, gender, use of a safety belt, vehicle's age, and road conditions were taken into account. It was observed that those driving metallic, white, yellow, red, or blue cars were less prone to accidents than those with brown, black, or green cars. Black and green cars showed a rising increment in their accident rate.
The study showed that when driving a grey-colored car, the risk of having an accident is two-and-a-half times lower than in a brown-colored car, and that black and green vehicles have at least twice the number of accidents as grey, red, yellow, and blue cars.
Additionally, in conditions of reduced visibility due to rain or fog, bright-colored cars are up to three times more visible than dark ones. Thus, black and brown vehicles are involved in 20% more crashes when weather conditions are adverse. The investigation asserts that the accident risk for brown and black cars includes all shades.
The accident-risk ranking according to color turned out as follows: brown 70%, black 66.7%, green 60%, white 33.3%, blue 30%, yellow 26.7%, red 23.3%, grey 20%, and silver 13.3%. The principal author of the study, Sue Furness, commented that the reason for the different rates of accidents among cars "could be because grey colors are more visible in contrast with the environment."
Another study carried out in Argentina by the Center for Road Experimentation and Safety (or "CESVI", Centro de Experimentación y Seguridad Vial) analyzed drivers perceived distance toward other vehicles on the basis of their color. It has been determined that objects become visible only when reflecting the light that falls on them. But no object reflects all of the light it receives. A certain amount of this light is absorbed by it, and only part is reflected.
Different surfaces reflect light differently, despite being illuminated by the same amount of light. Light-colored surfaces reflect between 60% and 80% of the light they receive, while dark ones reflect less than 30%. The light reflected by the object is what is seen.
Taking this into consideration, it can be asserted that dark-colored vehicles are more difficult to detect, due to their considerably inferior reflection ability.
According to a study carried out by the School of Public Health of the University of Auckland, New Zealand, that choice is very important when it comes to safety, because, for example, the risk of an accident in a silver-colored vehicle is five times lower than in a black one.
This study analyzed the effect of color and the risk of accident among over a thousand drivers and determined that brown, black, and green cars are involved in more accidents, whereas grey, red, and yellow ones are less accident-prone. This is because dark vehicles tend to "blend" into the surrounding area, rendering it more difficult to "pick them out" from the environment than light-colored cars.
In order to conduct this study, influential factors such as age, experience, speed, alcohol consumption, gender, use of a safety belt, vehicle's age, and road conditions were taken into account. It was observed that those driving metallic, white, yellow, red, or blue cars were less prone to accidents than those with brown, black, or green cars. Black and green cars showed a rising increment in their accident rate.
The study showed that when driving a grey-colored car, the risk of having an accident is two-and-a-half times lower than in a brown-colored car, and that black and green vehicles have at least twice the number of accidents as grey, red, yellow, and blue cars.
Additionally, in conditions of reduced visibility due to rain or fog, bright-colored cars are up to three times more visible than dark ones. Thus, black and brown vehicles are involved in 20% more crashes when weather conditions are adverse. The investigation asserts that the accident risk for brown and black cars includes all shades.
The accident-risk ranking according to color turned out as follows: brown 70%, black 66.7%, green 60%, white 33.3%, blue 30%, yellow 26.7%, red 23.3%, grey 20%, and silver 13.3%. The principal author of the study, Sue Furness, commented that the reason for the different rates of accidents among cars "could be because grey colors are more visible in contrast with the environment."
Another study carried out in Argentina by the Center for Road Experimentation and Safety (or "CESVI", Centro de Experimentación y Seguridad Vial) analyzed drivers perceived distance toward other vehicles on the basis of their color. It has been determined that objects become visible only when reflecting the light that falls on them. But no object reflects all of the light it receives. A certain amount of this light is absorbed by it, and only part is reflected.
Different surfaces reflect light differently, despite being illuminated by the same amount of light. Light-colored surfaces reflect between 60% and 80% of the light they receive, while dark ones reflect less than 30%. The light reflected by the object is what is seen.
Taking this into consideration, it can be asserted that dark-colored vehicles are more difficult to detect, due to their considerably inferior reflection ability.
8.02.2008
Combat computer-related eye issues
Computers have become an integral part of daily life. They're used at work, when shopping, at school, and often for recreational purposes. While computer usage certainly has its advantages, prolonged or constant use of computers can lead to certain problems, most notably eye strain and fatigue.
There are many computer tasks that are known offenders in regard to visual discomfort. These include intense games and graphics, tasks with few breaks from the screen, detailed tasks such as desktop publishing or computer assisted design (CAD), and work that requires frequent changes from looking at the screen to hard copy, such as with data entry.
What causes many of these vision problems is a reduced rate of blinking when engaged in computer use. Normally, a person blinks on average 12 to 15 times per minute. When using a computer, that number is significantly reduced. The end result is dry eyes, fatigue and strain. In fact, dry eyes, eye strain, and blurring are the common complaints eye doctors hear from frequent computer users. These complaints are often associated with headaches and neck and arm discomfort.
Maximizing Comfort
There are steps a person can take to improve eye health and comfort when using a computer. Here are some initial strategies to try:
·Place the monitor farther away, since eye strain is more pronounced when doing tasks close up. The screen should be no closer than 18 inches from the user. Many doctors say that 24 to 30 inches from the face is ideal.
·Reduce glare by adjusting the monitor contrast so that the screen is less bright. There are also specially designed screen filters that may help.
·Take frequent breaks. Depending upon computer use, move away from the work station every 30 to 60 minutes to rest the eyes.
·Exercise the eyes by looking away from the screen and focusing in on something farther away. Stretch the eyes by looking up and down, and far left and far right.
·Use moderate background lighting with supplemental task lighting for hard copy documents. The illumination from the screen should closely match the light reflected from the document.
·Place hard copy documents in a copy holder at the same distance away as the computer monitor.
Taking Further Steps
For those who find that these easy steps are not enough to eliminate eye problems, it could be time to talk to an optometrist. He or she can further assess the situation and either offer more strategies or prescribe lenses that will work to maximize comfort. Supplementary eye lubricants and ocular exercises and other vision therapy may be recommended.
There are steps a person can take to improve eye health and comfort when using a computer. Here are some initial strategies to try:
·Place the monitor farther away, since eye strain is more pronounced when doing tasks close up. The screen should be no closer than 18 inches from the user. Many doctors say that 24 to 30 inches from the face is ideal.
·Reduce glare by adjusting the monitor contrast so that the screen is less bright. There are also specially designed screen filters that may help.
·Take frequent breaks. Depending upon computer use, move away from the work station every 30 to 60 minutes to rest the eyes.
·Exercise the eyes by looking away from the screen and focusing in on something farther away. Stretch the eyes by looking up and down, and far left and far right.
·Use moderate background lighting with supplemental task lighting for hard copy documents. The illumination from the screen should closely match the light reflected from the document.
·Place hard copy documents in a copy holder at the same distance away as the computer monitor.
Taking Further Steps
For those who find that these easy steps are not enough to eliminate eye problems, it could be time to talk to an optometrist. He or she can further assess the situation and either offer more strategies or prescribe lenses that will work to maximize comfort. Supplementary eye lubricants and ocular exercises and other vision therapy may be recommended.
A person may also want to investigate special tints and coatings for lenses. Certain tints can make some individuals more comfortable under fluorescent illumination. And contrary to popular belief, anti-reflection coated lenses do not eliminate reflections from the screen but do reduce reflections off the spectacle lenses and may make users more comfortable.
For more information on computer-related eye strain, visit your eye doctor and discuss any trouble you may be having.
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