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#51 2017-12-22 14:11:02

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

Hi Monox D. I-Fly,

Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species, the Mekong giant catfish from Southeast Asia, the wels catfish of Eurasia and the piraíba of South America, to detritivores (species that eat dead material on the bottom), and even to a tiny parasitic species commonly called the candiru, Vandellia cirrhosa.

In contrast,

Electrophorus electricus : Electric eel, (Electrophorus electricus), elongated South American fish that produces a powerful electric shock to stun its prey, usually other fish.

Long, cylindrical, scaleless, and usually gray-brown (sometimes with a red underside), the electric eel can grow to 2.75 metres (9 feet) and weigh 22 kg (48.5 pounds). The tail region constitutes about four-fifths of the electric eel’s total length, which is bordered along the underside by an undulating anal fin that is used to propel the fish. Despite its name, it is not a true eel but is related to the characin fish, which include piranhas and neon tetras. The electric eel is one of the principal aquatic predators of the whitewater flooded forest known as varzea. In one fish survey of a typical varzea, electric eels made up more than 70 percent of the fish biomass. The electric eel is a sluggish creature that prefers slow-moving fresh water, where it surfaces every few minutes to gulp air. The mouth of the electric eel is rich with blood vessels that allow it to use the mouth as a lung. The vestigial gills are only used to eliminate carbon dioxide, not for oxygen uptake.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#52 2017-12-22 15:04:19

Monox D. I-Fly
Registered: 2015-12-02
Posts: 975

Re: Miscellany

ganesh wrote:

Despite its name, it is not a true eel but is related to the characin fish, which include piranhas and neon tetras.

Wait, after catfish, now piranha? Wow.


#53 2017-12-24 00:54:51

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

48) The Jazz Singer

The Jazz Singer, American musical film, released in 1927, that was the first feature-length movie with synchronized dialogue. It marked the ascendancy of “talkies” and the end of the silent-film era.

On Yom Kippur, cantor Rabinowitz (played by Warner Oland) looks forward to when his 13-year-old son, Jakie (Robert Gordon), will succeed him at the synagogue. However, after discovering that Jakie is singing in a saloon, the cantor beats him, and Jakie runs away from home. As an adult (Al Jolson), Jakie becomes a jazz singer, performing under the name Jack Robin. When his father falls ill before Yom Kippur, Jakie must choose between singing at the dress rehearsal of his new Broadway show or singing the Kol Nidre at the synagogue in his father’s place. Jakie finishes his number and rushes to the synagogue, where his father hears him singing the Kol Nidre and then dies, reconciled to Jakie.

Although widely credited with being the first talkie, the accolade is somewhat misleading. Other films had synchronized sound for music or sound effects prior to this film. The small studio Warner Brothers had bought a sound-on-disc system called Vitaphone and debuted the system in 1926 with Don Juan, a lavish costume drama featuring a score performed by the New York Philharmonic Orchestra. However, The Jazz Singer, the second Vitaphone feature, was the first full feature film to have a sound track that included dialogue (though only the musical numbers and some select conversations amounting to one-fourth of the film were recorded for sound). The first feature in which all the dialogue was recorded was another Warner Brothers Vitaphone film, Lights of New York (1928).

Comedians Eddie Cantor and George Jessel (who played the lead role in the 1925 play on which the movie is based) both turned down the film, leaving the historic role for Jolson. Studio executive Sam Warner, one of the founders of Warner Brothers and the creative force behind the film, died one day before the movie’s premiere, which was intentionally set for the day before Yom Kippur. One of Jolson’s first lines, “You ain’t heard nothin’ yet,” came to symbolize the arrival of the talking picture. The film’s financial success established Warner Brothers as a major studio, and the studio won an honorary Academy Award for “producing The Jazz Singer, the pioneer outstanding talking picture, which has revolutionized the industry.” There have been many remakes of the story onscreen and onstage, Jolson’s performance in blackface has long been studied for what it says about stereotypes and the problems of assimilation often encountered by ethnic groups.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#54 2017-12-25 21:29:13

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

49) Sound

Noise is defined as ‘unwanted sounds’, while sound is a term used for sensation that the brain receives when pressure variations in the air are detected by the ear. What is sound to one person can very well be noise to somebody else, but anyone who is exposed to noise is potentially at risk. The higher the level of noise, and the longer individuals are exposed to it, the more risk they have of suffering harm from it.

Millions of workers worldwide are exposed to noise levels that put their hearing at risk. Excessive noise is an occupational hazard with many adverse effects, not only to the workers involved with noisy operations but also to those around them. Its effects can lead to temporary or permanent hearing damage and can impair workers’ efficiency. Individuals suffering from poor hearing, whether it is due to their age or illness, can have their problems made worse by exposure to higher levels of noise at work. It can also lead to accidents due to limited speech communication, misunderstanding oral instructions and masking the sounds of approaching danger or warnings.

Main sources of noise at work

Noise is a common hazard and is present to some extent in almost all workplaces. It is the most common health hazard in industries such as entertainment, manufacturing, agriculture, ship-building, textiles, mining and quarrying, food and drink, woodworking, metal working and construction.

Some common sources of noise are:

loud music
the use of heavy machinery
workplace transport
electrical tools such as circular saws and cutter heads
production lines
pneumatic tools such as drills, grinders and riveting guns
electrical motors and generators
engineering processes such as metal fabrication
plant rooms where ventilation equipment has to run continuously.

Typical noise levels

Noise is measured in decibels (dB). There are two aspects to sound measurements:

the frequency of the sound
the intensity of the sound.

The decibel scale is logarithmic: a small increase in the decibel level is, in reality, a big increase in the noise level. For example, an increase of only 3dB doubles the noise level at the human ear and halves the time a person should be exposed to it once harmful levels are reached.

Hazardous noise levels

It is difficult to specify what level of noise is absolutely safe, as individuals are affected by noise differently. However, noise levels above 75–80 dB(A) are known to cause hearing damage. The louder the noise is, the less time it takes to cause damage. For example, noise levels at 85 dB(A) may take as long as eight hours to cause hearing damage, while noise at 100 dB(A) may start damaging hair cells in the ear after only 30 minutes.

To establish whether a hazardous level of noise exists within the workplace, employers need to check whether a normal conversation at a distance of about one metre can be carried out. If there is difficulty in communicating then it is likely that noise levels are high.

General signs of hearing loss

It's important to spot hearing loss as soon as possible because early signs can help to identify the problem quickly.

Early signs of hearing loss can include:

ringing in the ears
inability to hear soft and high-pitched sounds
muffling of speech and other sounds
trouble understanding conversations at a distance or in a crowd
listening to music or watching television with the volume higher than other people need
difficulty hearing the telephone or doorbell
finding it difficult to tell which direction noise is coming from
regularly feeling tired or stressed, from having to concentrate while listening
answering or responding inappropriately in conversations
reading lips or more intently watching people’s faces during conversations
feeling annoyed at other people because of not understanding them
feeling nervous about trying to hear and understand others.
Research suggests it takes 10 years from the time someone notices they have hearing loss before they do anything about it.

Occupational noise burden

Excessive noise is a global occupational health hazard with considerable social and physiological impacts. Exposure to loud noise from all sources accounts for about 20 per cent of adult-onset hearing loss, while 16 per cent of the disabling hearing loss in adults is attributed to occupational noise. Noise-induced hearing loss is considered the 15th most serious health problem in the world.

Noise-induced hearing loss is the most common reported occupational disease in Europe. Twenty per cent of Europe’s workers have to raise their voices to be heard for at least half of the time that they are at work, while seven per cent suffer from hearing difficulties. In 2000, 29 per cent of workers in the EU–15 and 35 per cent in the new member states reported being exposed to high-level noise at least one quarter of the time and 11 per cent all the time.

In the United Kingdom, it is estimated that there are more than 10 million individuals (about 1 in 6) with some degree of hearing impairment or deafness. Over one million workers are exposed to levels of noise that put their hearing at risk, with 17 per cent suffering hearing loss, tinnitus or other hearing-related conditions as a result of exposure to excessive noise at work.

Health effects of noise
When individuals are exposed to high levels of noise in the workplace, they can suffer from various adverse health effects. These health effects can be caused by a single exposure to a very loud noise or by exposure to raised levels of noise over a prolonged period of time.

The effects of noise on hearing depend on:

noise intensity or sound pressure
frequency or pitch of sound
exposure time
distance from source
individual susceptibility
other factors (life-style, age, disease, genetics and so on).
The most well-known effect of occupational noise is hearing impairment. However, it can also exacerbate other health conditions. Some individuals are more sensitive to noise than others and will suffer harm more readily through noise exposure.

The main health effects include the following:


Tinnitus (ringing in the ears) is the early sign of hearing damage. Excessive exposure to noise increases the risk of tinnitus. If the noise is impulsive, the risk can rise substantially. Tinnitus can be a very distressing condition and can lead to disturbed sleep and affected speech. There is no effective cure for this condition but there is treatment available for easing the symptoms. More information on Tinnitus is available from the UK’s National Health Service.

Noise-induced hearing loss

Noise-induced hearing loss occurs because excessive noise damages the delicate hearing mechanism of the inner ear. It is the most common preventable occupational health condition across the world. The level of noise that is likely to damage hearing varies depending on the individual’s characteristics and the duration for which they’re exposed to the noise.

Hearing loss is a common health problem that often develops with age (presbycusis). It is linked with genetic inheritance and other illnesses, and is also caused by exposure to excessive noise. Hearing loss is not always gradual: it can occur when an individual is exposed to very intense or loud noise for a short period of time such as a loud explosion. This condition is known as acoustic trauma.

Furthermore, the ear's sensitivity level decreases as a measure of protection against exposure to noise. This process is known as a shift in the threshold of hearing, meaning that only sounds louder than a certain level will be heard. The shift may be temporary or permanent. Short-term hearing loss can be experienced as a temporary threshold shift. It may occur suddenly after exposure to intense and/or loud noise, a situation most individuals have experienced at some point in their lives. Temporary threshold shift results in temporary hearing loss. However, repeated exposure to such intense or loud noise normally transforms this into a permanent loss, or permanent threshold shift.

Permanent threshold shift occurs when individuals have been regularly exposed to high levels of noise over a long period of time. It also occurs when exposed to noise repeatedly without sufficient time between exposures to allow recovery of normal hearing, resulting in permanent hearing damage. The UK’s National Health Service provides more information on hearing loss.

Loss of hearing can have a huge impact on an individual’s personal and work life. Once hearing has been damaged, there’s currently no known cure or effective treatment.

Effect on pregnancy

Exposure of pregnant workers to high noise levels can affect the unborn child. Research suggests that prolonged exposure of the unborn child to high noise levels during pregnancy may have an effect on a child’s later hearing and that low frequencies have a greater potential for causing harm.

Physiological effects

Noise can have an effect on the cardiovascular system, resulting in an increase in blood pressure and the release of catecholamines in the blood. An increased level of catecholamines in the blood is associated with stress.

Occupational stress

Occupational stress rarely has a single cause and often arises from the interaction of several risk factors. Persistent noise in the work environment can be a stressor even at quite low levels.

Other effects

Excessive levels of noise can increase the likelihood of undesired events or incidents by:

distracting workers, such as drivers
making it harder for workers to hear and understand instructions correctly
masking the sound of approaching danger and warning signals
contributing to irritation and annoyance that may lead to human error.

An individual’s performance in tasks demanding continuous attention (safety-critical tasks) may be affected by noise as it can distract them, resulting in poor judgements and decision-making process.

Note: Exposure to excessive noise is not the only risk factor that can result in hearing impairment. Certain chemical agents known as ototoxic chemicals and medications can also cause damage to the hearing. There are over 200 identified chemical agents that may affect hearing on temporarily or permanent basis. Exposure to such chemicals may increase the effects of noise on hearing loss.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#55 2017-12-29 00:22:06

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

50) Hibernation

What is Hibernation?

For most animals finding enough food in winter can be difficult when the main source of food like insects or green plants is in short supply.

Some animals solve this problem by hibernating. Hibernation is a deep sleep that helps them to save energy and survive the winter without eating much.

During hibernation the animal’s body temperature drops, and its heartbeat and its breathing slow down so that it does not use much energy.

Hibernating animals get ready for their winter sleep by eating extra food and storing it as body fat which they then use as energy while sleeping.  There are two types of fat – regular white fat and brown fat.  The brown fat forms patches near the animal’s brain, heart and lungs. It sends a quick burst of energy to warm these organs first when it is time to wake up.

Some of the hibernating animals include fish, frogs and turtles, which have no way to keep warm during winter. They shelter under logs, rocks and fallen leaves in the water. When the weather gets cold, they move down to the bottom of lakes and ponds and some even burrow into the mud.

Some insects also hibernate and to keep warm they find holes in the ground, under tree bark or in rotting logs. Can you name some of the animals that hibernate in the winter?

Some hibernators go into such a deep sleep that it is almost impossible to wake them, and they appear to be dead.

If the temperature falls too low some animals will awaken slightly and shiver to warm up a bit.  Even when the weather is severe, hibernators may wake up for a short period every few weeks to use their ‘toilet rooms’ and eat a little food if it is available.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#56 2017-12-31 08:14:04

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

51) The Golgi Apparatus

The Golgi apparatus (GA), also called Golgi body or Golgi complex and found universally in both plant and animal cells, is typically comprised of a series of five to eight cup-shaped, membrane-covered sacs called cisternae that look something like a stack of deflated balloons. In some unicellular flagellates, however, as many as 60 cisternae may combine to make up the Golgi apparatus. Similarly, the number of Golgi bodies in a cell varies according to its function. Animal cells generally contain between ten and twenty Golgi stacks per cell, which are linked into a single complex by tubular connections between cisternae. This complex is usually located close to the cell nucleus.

Due to its relatively large size, the Golgi apparatus was one of the first organelles ever observed. In 1897, an Italian physician named Camillo Golgi, who was investigating the nervous system by using a new staining technique he developed (and which is still sometimes used today; known as Golgi staining or Golgi impregnation), observed in a sample under his light microscope a cellular structure that he termed the internal reticular apparatus. Soon after he publicly announced his discovery in 1898, the structure was named after him, becoming universally known as the Golgi apparatus. Yet, many scientists did not believe that what Golgi observed was a real organelle present in the cell and instead argued that the apparent body was a visual distortion caused by staining. The invention of the electron microscope in the twentieth century finally confirmed that the Golgi apparatus is a cellular organelle.

The Golgi apparatus is often considered the distribution and shipping department for the cell's chemical products. It modifies proteins and lipids (fats) that have been built in the endoplasmic reticulum and prepares them for export outside of the cell or for transport to other locations in the cell. Proteins and lipids built in the smooth and rough endoplasmic reticulum bud off in tiny bubble-like vesicles that move through the cytoplasm until they reach the Golgi complex. The vesicles fuse with the Golgi membranes and release their internally stored molecules into the organelle. Once inside, the compounds are further processed by the Golgi apparatus, which adds molecules or chops tiny pieces off the ends. When completed, the product is extruded from the GA in a vesicle and directed to its final destination inside or outside the cell. The exported products are secretions of proteins or glycoproteins that are part of the cell's function in the organism. Other products are returned to the endoplasmic reticulum or may undergo maturation to become lysosomes.

The modifications to molecules that take place in the Golgi apparatus occur in an orderly fashion. Each Golgi stack has two distinct ends, or faces. The cis face of a Golgi stack is the end of the organelle where substances enter from the endoplasmic reticulum for processing, while the trans face is where they exit in the form of smaller detached vesicles. Consequently, the cis face is found near the endoplasmic reticulum, from whence most of the material it receives comes, and the trans face is positioned near the plasma membrane of the cell, to where many of the substances it modifies are shipped. The chemical make-up of each face is different and the enzymes contained in the lumens (inner open spaces) of the cisternae between the faces are distinctive. Illustrated in Figure 2 is a fluorescence digital image taken through a microscope of the Golgi apparatus (pseudocolored red) in a typical animal cell. Note the close proximity of the Golgi membranes to the cell nucleus.

Proteins, carbohydrates, phospholipids, and other molecules formed in the endoplasmic reticulum are transported to the Golgi apparatus to be biochemically modified during their transition from the cis to the trans poles of the complex. Enzymes present in the Golgi lumen modify the carbohydrate (or sugar) portion of glycoproteins by adding or subtracting individual sugar monomers. In addition, the Golgi apparatus manufactures a variety of macromolecules on its own, including a variety of polysaccharides. The Golgi complex in plant cells produces pectins and other polysaccharides specifically needed by for plant structure and metabolism. The products exported by the Golgi apparatus through the trans face eventually fuse with the plasma membrane of the cell. Among the most important duties of the Golgi apparatus is to sort the wide variety of macromolecules produced by the cell and target them for distribution to their proper location. Specialized molecular identification labels or tags, such as phosphate groups, are added by the Golgi enzymes to aid in this sorting effort.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#57 2018-01-01 12:56:08

Monox D. I-Fly
Registered: 2015-12-02
Posts: 975

Re: Miscellany

ganesh wrote:

Some of the hibernating animals include fish, frogs and turtles, which have no way to keep warm during winter. They shelter under logs, rocks and fallen leaves in the water. When the weather gets cold, they move down to the bottom of lakes and ponds and some even burrow into the mud.

Wow, so fish sleep with their eyes open for a season? Must be very hard thing to do.


#58 2018-01-01 14:42:30

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

Monox D. I-Fly wrote:
ganesh wrote:

Some of the hibernating animals include fish, frogs and turtles, which have no way to keep warm during winter. They shelter under logs, rocks and fallen leaves in the water. When the weather gets cold, they move down to the bottom of lakes and ponds and some even burrow into the mud.

Wow, so fish sleep with their eyes open for a season? Must be very hard thing to do.

Vision in fishes

Vision is an important sensory system for most species of fish. Fish eyes are similar to the eyes of terrestrial vertebrates like birds and mammals, but have a more spherical lens. Birds and mammals (including humans) normally adjust focus by changing the shape of their lens, but fish normally adjust focus by moving the lens closer to or further from the retina. Fish retinas generally have both rod cells and cone cells (for scotopic and photopic vision), and most species have colour vision. Some fish can see ultraviolet and some are sensitive to polarized light.

Among jawless fish, the lamprey  has well-developed eyes, while the hagfish has only primitive eyespots. The ancestors of modern hagfish, thought to be the protovertebrate were evidently pushed to very deep, dark waters, where they were less vulnerable to sighted predators, and where it is advantageous to have a convex eye-spot, which gathers more light than a flat or concave one. Fish vision shows evolutionary adaptation to their visual environment, for example deep sea fish have eyes suited to the dark environment.

Water as a visual environment

Fish and other aquatic animals live in a different light environment than terrestrial species. Water absorbs light so that with increasing depth the amount of light available decreases quickly. The optical properties of water also lead to different wavelengths of light being absorbed to different degrees. For example, visible light of long wavelengths (e.g. red, orange) is absorbed quicker than light of shorter wavelengths (green, blue). Ultraviolet light (even shorter wavelength than violet) is absorbed quicker yet. Besides these universal qualities of water, different bodies of water may absorb light of different wavelengths due to varying salt and/or chemical presence in the water.

Structure and function

Fish eyes are broadly similar to those of other vertebrates – notably the tetrapods (amphibians, reptiles, birds and mammals – all of which evolved from a fish ancestor). Light enters the eye at the cornea, passing through the pupil to reach the lens. Most fish species seem to have a fixed pupil size, but elasmobranches (like sharks and rays) have a muscular iris which allows pupil diameter to be adjusted. Pupil shape varies, and may be e.g. circular or slit-like.

Lenses are normally spherical but can be slightly elliptical in some species. Compared to terrestrial vertebrates, fish lenses are generally more dense and spherical. In the aquatic environment there is not a major difference in the refractive index of the cornea and the surrounding water (compared to air on land) so the lens has to do the majority of the refraction. Due to "a refractive index gradient within the lens — exactly as one would expect from optical theory" the spherical lenses of fish are able to form sharp images free from spherical aberration.

Once light passes through the lens it is transmitted through a transparent liquid medium until it reaches the retina, containing the photoreceptors. Like other vertebrates, the photoreceptors are on the inside layer so light must pass through layers of other neurons before it reaches them. The retina contains rod cells and cone cells.

The retina

Within the retina, rod cells provide high visual sensitivity (at the cost of acuity), being used in low light conditions. Cone cells provide higher spatial and temporal resolution than rods can, and allow for the possibility of colour vision by comparing absorbances across different types of cones which are more sensitive to different wavelengths. The ratio of rods to cones depends on the ecology of the fish species concerned, e.g., those mainly active during the day in clear waters will have more cones than those living in low light environments. Colour vision is more useful in environments with a broader range of wavelengths available, e.g., near the surface in clear waters rather than in deeper water where only a narrow band of wavelengths persist.

The distribution of photoreceptors across the retina is not uniform. Some areas have higher densities of cone cells, for example (see fovea). Fish may have two or three areas specialized for high acuity (e.g. for prey capture) or sensitivity (e.g. from dim light coming from below). The distribution of photoreceptors may also change over time during development of the individual. This is especially the case when the species typically moves between different light environments during its life cycle (e.g. shallow to deep waters, or fresh water to ocean). or when food spectrum changes accompany the growth of a fish as seen with the Antarctic icefish Champsocephalus gunnari.

Some species have a tapetum, a reflective layer which bounces light that passes through the retina back through it again. This enhances sensitivity in low light conditions, such as nocturnal and deep sea species, by giving photons a second chance to be captured by photoreceptors. However this comes at a cost of reduced resolution. Some species are able to effectively turn their tapetum off in bright conditions, with a dark pigment layer covering it as needed.

The retina uses a lot of oxygen compared to most other tissues, and is supplied with plentiful oxygenated blood to ensure optimal performance.

Humans have a vestibulo-ocular reflex, which is a reflex eye movement that stabilizes images on the retina during head movement by producing an eye movement in the direction opposite to head movement, thus preserving the image on the center of the visual field. In a similar manner, fish have a vestibulo-ocular reflex which stabilizes visual images on the retina when it moves its tail.


Accommodation is the process by which the vertebrate eye adjusts focus on an object as it moves closer or further away. Whereas birds and mammals achieve accommodation by deforming the lens of their eyes, fish and amphibians normally adjust focus by moving the lens closer or further from the retina. They use a special muscle which changes the distance of the lens from the retina. In bony fishes the muscle is called the retractor lentis, and is relaxed for near vision, whereas for cartilaginous fishes the muscle is called the protractor lentis, and is relaxed for far vision. Thus bony fishes accommodate for distance vision by moving the lens further from the retina, while cartilaginous fishes accommodate for near vision by moving the lens closer to the retina.

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#59 2018-01-02 22:26:35

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

52) Hartsfield–Jackson Atlanta International Airport

Hartsfield–Jackson Atlanta International Airport (IATA: ATL, ICAO: KATL, FAA LID: ATL), also known as Atlanta Airport, Hartsfield, or Hartsfield–Jackson, is an international airport located 7 miles (11 km) south of Atlanta's central business district, in the U.S. state of Georgia.

It has been the world's busiest airport by passenger traffic since 1998; and by number of landings and take-offs from 2005 to 2013, losing that title to Chicago–O'Hare in 2014, but regaining it a year later. Hartsfield–Jackson held its ranking as the world's busiest airport in 2012, both in passengers and number of flights, by accommodating 100 million passengers (more than 260,000 passengers daily) and 950,119 flights. Many of the nearly one million flights are domestic flights from within the United States, where the airport serves as a major hub for travel throughout the southeastern region of the country. The airport has 209 domestic and international gates. ATL covers 4,700 acres (1,902 ha) of land and has five parallel runways.

Hartsfield–Jackson is the primary hub of Delta Air Lines, and is a focus city for low-cost carriers Frontier Airlines, Southwest Airlines, and Spirit Airlines. With just over 1,000 flights a day, the Delta Air Lines hub is the world's largest hub. Delta Air Lines flew 75.4% of the airport's passengers in February 2016, Southwest flew 9.2%, and American Airlines flew 2.5%. In addition to hosting Delta Air Lines corporate headquarters, Hartsfield–Jackson is also the home of Delta's Technical Operations Center, which is the airline's primary maintenance, repair and overhaul arm. The airport has international service within North America and to countries in South America, Central America, Europe, Asia, and Africa. As an international gateway to the United States, Hartsfield–Jackson ranks sixth.

The airport is mostly in unincorporated areas in Fulton and Clayton counties. However, the airport spills into the city limits of Atlanta, College Park, and Hapeville. The airport's domestic terminal is served by MARTA's Red and Gold rail lines.

Ask most people to name the location of the world's busiest airport, and you're likely to hear guesses ranging from New York and London to Beijing and Tokyo.

But that title goes to Hartsfield-Jackson International Airport, in Atlanta.

A major power outage sent the air hub into disarray over the weekend, as thousands of passengers were hit with major cancellations and delays. But the news left many people most surprised to learn that Hartsfield-Jackson is the world's busiest.

According to Airports Council International, more than 104 million passengers passed through the airport in 2016, a 2.6 percent increase over 2015. Hartsfield-Jackson has been the world's busiest airport by passenger traffic since 1998.

That means the airport in America's Southeast is busier than counterparts in Beijing, Dubai, Los Angeles and Tokyo— which round up the top five in 2016 by passenger traffic:

Geography ... and Delta

Hartsfield-Jackson plays a critical role as a connecting hub for the larger United States, which is the world's biggest economy.

According to a fact sheet released by Hartsfield-Jackson, Atlanta is within a two-hour flight for 80 percent of the U.S. population.

The airport is a major connection for flights, serving 150 U.S. destinations and more than 75 destinations in 50 countries.

It handles some 2,500 flights and 275,000 passengers a day.

Hartsfield-Jackson airport is home to one of the world's largest carriers, Delta Air Lines, which was founded in Georgia. It began as a crop-dusting company before temporarily moving to Louisiana in 1925.

Last year, Delta renewed its lease agreement for another 20 years.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#60 2018-01-03 12:42:36

Monox D. I-Fly
Registered: 2015-12-02
Posts: 975

Re: Miscellany

ganesh wrote:

For example, visible light of long wavelengths (e.g. red, orange) is absorbed quicker than light of shorter wavelengths (green, blue).

Kinda ironic since water itself looks green and/or blue.


#61 2018-01-03 14:31:26

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

Monox D. I-Fly wrote:

Kinda ironic since water itself looks green and/or blue.

"The ocean looks blue because red, orange and yellow (long wavelength light) are absorbed more strongly by water than is blue (short wavelength light). So when white light from the sun enters the ocean, it is mostly the blue that gets returned. Same reason the sky is blue."

In other words, the color of the ocean and the color of the sky are related but occur independently of each other: in both cases, the preferential absorption of long-wavelength (reddish) light gives rise to the blue. Note that this effect only works if the water is very pure; if the water is full of mud, algae or other impurities, the light scattered off these impurities will overwhelm the water's natural blueness.

Gross then asks, "So why are sunsets orange?" Several people to wrote in to correct or clarify that comment.

Perhaps the most helpful response came from Michael Kruger of the department of physics at the University of Missouri. He sent the following reaction:

"The answer to why the sky is blue isn't quite correct. The sky is blue not because the atmosphere absorbs the other colors, but because the atmosphere tends to scatter shorter wavelength (blue) light to a greater extent than longer wavelength (red) light. Blue light from the sun is scattered every which way, much more so than the other colors, so when you look up at the daytime sky you see blue no matter where you look. This scattering is called 'Rayleigh scattering'; the amount of scattering goes as the frequency of the light to the 4th power. By the way, this effect is most prevalent when the particles that do the scattering are smaller than the wavelength of light, as is the case for the nitrogen and oxygen molecules in the atmosphere.

"Now we are in a position to figure out why sunsets are reddish! When the sun is setting, the light that reaches you has had to go through lots more atmosphere than when the sun is overhead, hence the only color light that is not scattered away is the long wavelength light, the red.

"We can also answer why clouds, milk, powdered sugar and salt are white. The particles in these materials that are responsible for scattering the light are larger than the wavelength of light. Consequently, all colors of light are scattered by more or less the same amount. Much of the scattering in milk is due to the lipids (fat). If you take out the fat, the milk will not scatter as much light; that is probably why skim milk looks the way it does.

Have you ever wondered why the ocean is blue? Have you ever wondered why the ocean is sometimes another color, like green, instead of blue? Here's the science behind the color of the sea.

Answer: There are a few reasons why the ocean is blue. The best answer is that the ocean is blue because it is mostly water, which is blue in large quantities. When light strikes water, like sunlight, the water filters the light so that red is absorbed and some blue is reflected.

Blue also travels further through water than light with longer wavelengths (red, yellow, green) though very little light reaches deeper than 200 meters (656 feet), and no light at all penetrates beyond 2,000 meters (3,280 feet).

Another reason the ocean appears blue is because it reflects the color of the sky. Tiny particles in the ocean act as reflective mirrors so a large part of the color you see depends on what is around the ocean.

Sometimes the ocean appears other colors besides blue. For example, the Atlantic off the East Coast of the United States usually appears green. This is due to the presence of algae and plant life. The ocean may appear gray under a cloudy sky or brown when the water contains a lot of sediment, as when a river empties into the sea or after the water has been stirred up by a storm.

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#62 2018-01-05 00:37:24

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

53) Hyperglycemia

Hyperglycemia means high (hyper) glucose (gly) in the blood (emia). Your body needs glucose to properly function. Your cells rely on glucose for energy. Hyperglycemia is a defining characteristic of diabetes—when the blood glucose level is too high because the body isn't properly using or doesn't make the hormone insulin.

You get glucose from the foods you eat. Carbohydrates, such as fruit, milk, potatoes, bread, and rice, are the biggest source of glucose in a typical diet. Your body breaks down carbohydrates into glucose, and then transports the glucose to the cells via the bloodstream.

Body Needs Insulin

However, in order to use the glucose, your body needs insulin. This is a hormone produced by the pancreas. Insulin helps transport glucose into the cells, particularly the muscle cells.

People with type 1 diabetes no longer make insulin to help their bodies use glucose, so they have to take insulin, which is injected under the skin. People with type 2 diabetes may have enough insulin, but their body doesn't use it well; they're insulin resistant. Some people with type 2 diabetes may not produce enough insulin.

People with diabetes may become hyperglycemic if they don't keep their blood glucose level under control (by using insulin, medications, and appropriate meal planning). For example, if someone with type 1 diabetes doesn't take enough insulin before eating, the glucose their body makes from that food can build up in their blood and lead to hyperglycemia.

Your endocrinologist will tell you what your target blood glucose levels are. Your levels may be different from what is usually considered as normal because of age, pregnancy, and/or other factors.

Fasting hyperglycemia is defined as when you don't eat for at least eight hours. Recommended range without diabetes is 70 to 130mg/dL. (The standard for measuring blood glucose is "mg/dL" which means milligrams per deciliter.) If your blood glucose level is above 130mg/dL, that's fasting hyperglycemia. Fasting hyperglycemia is a common diabetes complication.

Postprandial or reactive hyperglycemia occurs after eating (postprandial means "after eating"). During this type of hyperglycemia, your liver doesn't stop sugar production, as it normally would directly after a meal, and stores glucose as glycogen (energy sugar stores). If your postprandial (1-2 hours after eating) blood glucose level is above 180mg/dL, that's postprandial or reactive hyperglycemia.

However, it's not just people with diabetes who can develop hyperglycemia. Certain medications and illnesses can cause it, including beta blockers, steroids, and bulimia.

This article will focus on hyperglycemia caused by diabetes.

Early Hyperglycemia Symptoms

Early symptoms of hyperglycemia, or high blood glucose (sugar), may serve as a warning even before you test your glucose level. Typical symptoms may include:

Increased thirst and/or hunger
Frequent urination
Sugar in your urine
Blurred vision

Ketoacidosis: When Hyperglycemia Becomes Severe for People with Type 1 Diabetes

If you have type 1 diabetes, it is important to recognize and treat hyperglycemia because if left untreated it can lead to ketoacidosis. This happens because without glucose, the body's cells must use ketones (toxic acids) as a source of energy. Ketoacidosis develops when ketones build up in the blood. It can become serious and lead to diabetic coma or even death. According to the American Diabetes Association, ketoacidosis affects people with type 1 diabetes, but it rarely affects people with type 2 diabetes.

Many symptoms of ketoacidosis are similar to hyperglycemia. The hallmarks of ketoacidosis are:

High level of ketones in the urine
Shortness of breath
Fruit-smelling breath
Dry mouth

Additionally, stomach pain, nausea, vomiting, and confusion may accompany ketoacidosis. Immediate medical attention is highly recommended if you have any of these symptoms.

Some people with diabetes are instructed by their doctor to regularly test ketone levels. Ketone testing is performed two ways: using urine or using blood. For a urine test, you dip a special type of test strip into your urine. For testing blood ketones, a special meter and test strips are used. The test is performed exactly like a blood glucose test. If ketone testing is part of your self-monitoring of diabetes, your healthcare professional will provide you with other information including prevention.

Hyperosmolar Hyperglycemic Nonketotic Syndrome (HHNS): When Hyperglycemia Becomes Severe for People with Type 2 Diabetes

Hyperosmolar hyperglycemic nonketotic syndrome (HHNS) is very rare, but you should be aware of it and know how to handle it if it occurs. HHNS is when your blood glucose level goes way too high—you become extremely hyperglycemic. HHNS affects people with type 2 diabetes.

HHNS is most likely to occur when you're sick, and elderly people are most likely to develop it. It starts when your blood glucose level starts to climb: when that happens, your body will try to get rid of all the excess glucose through frequent urination. That dehydrates your body, and you'll become very thirsty.

Unfortunately, when you're sick, it's sometimes more difficult to rehydrate your body, as you know you should. For example, it might be difficult to keep fluids down. When you don't rehydrate your body, the blood glucose level continues to climb, and it can eventually go so high that it could send you into a coma.

To avoid hyperosmolar hyperglycemic nonketotic syndrome, you should keep close watch on your blood glucose level when you're sick (you should always pay attention to your blood glucose level, but pay special attention when you're sick).

Talk to your healthcare professional about having a sick-day plan to follow that will help you avoid HHNS.

You should also be able to quickly recognize the signs and symptoms of HHNS, which include:

Extremely high blood glucose level (over 600 mg/dL)
Dry mouth
High fever (over 101ºF)
Vision loss

Treating Hyperglycemia

Treating hyperglycemia is a matter of working on preventing it.

If your blood glucose level is consistently too high, talk with your doctor about what you can do to keep it in a more normal range. He or she may suggest:

Medication Adjustment: Your doctor may adjust your insulin (or glucose-lowering medication) dose or when you take it to help prevent hyperglycemia.

Meal Plan Help: A healthy diet and proper meal planning can help you avoid hyperglycemia. This includes eating often, watching intake of sugar and carbohydrates, limiting use of alcohol, and eating a diet rich in vegetables, fruit and whole grains. If you are having difficulty planning meals, talk to your doctor or dietitian.

Exercise: Regular exercise is important (even if you don't have diabetes). Maintaining a healthy level of activity can help you keep your blood glucose level in a normal range.

However, if you develop hyperglycemia and/or ketones are present in your urine, don't exercise. Hyperglycemia and/or ketones in the urine mean exercise will cause your blood glucose to rise higher.

Preventing Hyperglycemia

The easiest way to prevent hyperglycemia is to control your diabetes. That includes knowing the early symptoms—no matter how subtle. Remember, there are many aspects of your diabetes care you can control:

Taking your insulin (or glucose-lowering medication) as prescribed
Avoiding consuming too many calories (i.e., sugary beverages)
Consuming the right types and grams of carbohydrates
Controlling stress
Staying active (exercising)
Going to your regularly scheduled doctor's appointments

Hyperglycemia is a common complication of diabetes, but through medication, exercise, and careful meal planning, you can keep your blood glucose level from going too high—and that can help you in the long-run.

Keeping your blood glucose levels in the recommended ranges throughout the day will help you avoid long-term complications of diabetes, such as:

Eye damage
Heart attack—or other cardiovascular complications
Kidney damage
Nerve damage
Problems with healing wounds

By maintaining your blood glucose levels—and avoiding hyperglycemia—you can reduce your risk of all these complications.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#63 2018-01-05 02:25:14

Monox D. I-Fly
Registered: 2015-12-02
Posts: 975

Re: Miscellany

ganesh wrote:

Answer: There are a few reasons why the ocean is blue. The best answer is that the ocean is blue because it is mostly water, which is blue in large quantities. When light strikes water, like sunlight, the water filters the light so that red is absorbed and some blue is reflected.

Sometimes the relation between water and light confuses me. I mean, water is supposed to be transparent, but sea is blue and rain is white.


#64 2018-01-05 02:57:58

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

Hi Monox D. I-Fly,

ganesh wrote:

There are a few reasons why the ocean is blue. The best answer is that the ocean is blue because it is mostly water, which is blue in large quantities. When light strikes water, like sunlight, the water filters the light so that red is absorbed and some blue is reflected.

Blue also travels further through water than light with longer wavelengths (red, yellow, green) though very little light reaches deeper than 200 meters (656 feet), and no light at all penetrates beyond 2,000 meters (3,280 feet).

Another reason the ocean appears blue is because it reflects the color of the sky. Tiny particles in the ocean act as reflective mirrors so a large part of the color you see depends on what is around the ocean.

Sometimes the ocean appears other colors besides blue. For example, the Atlantic off the East Coast of the United States usually appears green. This is due to the presence of algae and plant life. The ocean may appear gray under a cloudy sky or brown when the water contains a lot of sediment, as when a river empties into the sea or after the water has been stirred up by a storm.

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#65 2018-01-06 14:51:58

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

54) Caspian Sea

Caspian Sea: Largest Inland Body of Water

The Caspian Sea is the Earth's largest inland body of water. It lies at the junction of Europe and Asia, with the Caucasus Mountains to the west and the steppes of Central Asia to the east. It is bordered by Russia to the northwest, Azerbaijan to the west, Iran to the south, Turkmenistan to the southeast and Kazakhstan to the northeast.

Ownership of the sea's resources is a contentious issue among its surrounding countries. The Caspian Sea is rich with oil and natural gas, making access to it a high-stakes proposition. These complicated socio-cultural and political aspects, as well as the geographic and environmental features, make the Caspian Sea an interesting subject for researchers.

"In some ways, it connects several countries that share no land border and in other ways it serves as buffer between states of different politics and ideologies," said Michael Kukral, author and professor of geography at the Rose-Hulman Institute of Technology in Ohio.

Facts and figures

Surface area: 143,244 square miles (371,000 square kilometers)
Maximum depth: 3,363 feet (1,025 meters)
Average depth: 692 feet (211 m)
Length: 640 miles (1,030 km)
Maximum width: 270 miles (435 km)
Minimum width: 124 miles (200 km)
Coastline area: 4,237 miles (6,820 km)
Water volume: 18,761 cubic miles (78,200 cubic km)
Altitude: 72 feet below sea level (22 m below sea level).

The Caspian Depression, a flat, lowland region encompassing the northern area of the Caspian Sea, is one of the lowest points on Earth.


"The Caspian Sea is located in a dry region of the world," Kukral told Live Science. Nevertheless, during harsh winters its entire northern half can freeze.

There are three distinct regions of the Caspian Sea. "In the north is a low-lying coastal plain, sandy, hot and humid," Kukral said. This area has the shallowest water in the Caspian, about 20 feet (4 to 5 m).

The Middle Caspian plunges in depth to about 620 feet (190 m). The western seabed slopes swiftly while the eastern gradates gently, according to New World Encyclopedia. The shores are hilly.

The Southern Caspian reaches depths of more than 3,300 feet (1,000 m) and holds most of the water. Kukral described the southern shores as lined with "cliffs and outcroppings overlooking the water where Persian elites often built homes."

The Caspian Sea is endorheic, meaning it has no natural outlets. More than 130 rivers flow into the Caspian Sea, according to Natural History Magazine, none of which are in the east. The primary tributary is the Volga River in the north, which provides about 80 percent of the inflowing water. The Ural River, also in the north, and the Kura River in the west, are also significant tributaries. The inflowing fresh water from these rivers dilute the water. Salinity changes from north to south, from 1.0 to 13.5 parts per thousand (ppt), according to Casp Info, a data-management project about the Caspian Sea funded by the European Union. By contrast, the North Atlantic Ocean has a salinity of 37 ppt, according to Encyclopedia Britannica. 

Because it has no outflow, the amount of rainfall in the regions of the rivers can greatly impact the water level of the Caspian Sea, according to GRID-Arendal, an environmental information center. Human-constructed dams built during the last two centuries have also changed water levels. Scientists theorize that tectonic movement and sedimentation changes could be other factors. In recent years, climate change has played a major role. More extreme weather patterns have increased rainfall in Russia, which brings more water into the Volga River and Caspian Sea. But scientists have also seen evidence that overall warmer temperatures could cause the Caspian Sea to dry up.

Scientists estimate that human-caused factors, including oil spills, which limit evaporation by covering the water with a thin film, account for 3 to 5 percent of water level variation, according to Natural History Magazine.

There are approximately 50 small, mostly uninhabited islands in the Caspian Sea, according to New World Encyclopedia. Most are in the north, but the largest island, Ogurja Ada, is in the south.

The Caspian Sea is next to the world's largest lagoon, according to Lakepedia. The 6,949-square-mile (18,000 square km) Kara-Bogaz Gol lagoon is on the eastern coast of the Caspian Sea and is separated from it by sand bars. A dam was built between the Caspian Sea and Kara-Bogaz Gol in 1980 but it was removed in 1992 because of the changes it caused to water levels.

A lake or a sea?

Despite its name, the Caspian Sea can be called either a lake or a sea. Kukral refers to it as a lake, as do many scholars. It has historically been considered a sea because of its size and its saline water, but it embodies many characteristics of lakes. Much of the confusion comes because there are no internationally agreed-upon definitions for seas or lakes.

Seas are often defined by connection to the ocean or another sea via salt water, which the Caspian Sea is not. Seas are usually partially enclosed by land, according to the National Oceanic and Atmospheric Administration, but the Caspian Sea is entirely enclosed by land. Seas are typically salt water. While the Caspian Sea is not fresh water, its salty water is diluted by the inflow of fresh water, especially in the north.

The question of whether it is a lake or a sea has political and economic ramifications, wrote Hanna Zimnitskaya in a 2011 Journal of Eurasian Studies article. If the Caspian Sea is a lake, then the United Nations and international law have no control over its waters, she wrote. If it is a sea, international organizations can have input on its use.

This is especially important because its energy resources. "Petroleum resources around and under the Caspian Sea make it an economic natural resource and a political issue of access and ownership," Kukral said.

If the Caspian Sea is a lake, it contains 40 percent of all lake water in the world. "It is the world's largest lake," Kukral said.


The Caspian Sea is a remnant of the ancient Paratethys Sea, part of the Tethys Ocean that existed 50 million to 60 million years ago. At that time, the Tethys Ocean was connected to the Atlantic and Pacific oceans, according to Over millennia, continental platforms shifted, and the Tethys Ocean lost its connections to other oceans. Much of it evaporated during hot and dry periods, and eventually the Caspian Sea, the Black Sea and the Aral Sea formed. The Caspian Sea is estimated to be about 30 million years old. The salt water from the Tethys Sea remained and accounts for the Caspian Sea's salinity.

According to the New World Encyclopedia, archaeologists estimate that humans inhabited the area around 75,000 years ago. It is named after the Caspi Tribe, which settled on its southwestern shore. By the 10th century, small oil wells dotted the shores of the Caspian Sea, according to the State Oil Company of Azerbaijan Republic (SOCAR). Europeans learned of the resource-rich area and began traveling to the Caspian Sea to investigate in the 16th century. The first offshore oil well was drilled in 1820. Today, the oil and gas industry is prominent in the area. Other businesses include salt extraction, fishing and tourism along the coasts.

The water level of the Caspian Sea has fluctuated throughout history, according to GRID-Arendal. From the mid-19th to late 20th century, the water level varied by more than 12 feet (3.6 m). In 1977, the Caspian Sea flooded and caused widespread destruction. Since then, several more floods have occurred. Since 1978, the water level has risen almost 7.4 feet (2.2 m), according to the Pars Times.


The Caspian Sea is known for its biodiversity, Kukral said. It is considered an independent zoogeographical region because of its unique qualities, according to the World Wildlife Fund.

In many areas, the shores are dotted with shallow saline pools in which birds, small fish, crustaceans and invertebrates thrive. Birds are present throughout the year, and many species use the Caspian Sea as a migratory refuge. Nearly 2,000 species and subspecies of animals live in and around the Caspian Sea, according to Casp Info. About 400 of them are endemic to the area, including the Caspian gull, Caspian turn, spur-thighed tortoise, Horsfield's tortoise, Caspian white fish, Caspian salmon and Caspian seal, the only aquatic mammal in the area. Nearby petroglyphs suggest that dolphins and porpoises may have once lived in the Caspian Sea, according to the Smithsonian Institution.

The most famous and financially valuable animal in the region is the beluga sturgeon, sometimes called the European or Caspian sturgeon. The world's largest freshwater fish, the beluga sturgeon is known for its eggs, which are processed into caviar. The majority of the world's beluga caviar comes from the Caspian Sea. This has caused problems with overfishing. Dams have also destroyed much of their spawning grounds, and pesticides used in land agriculture have limited their fertility. The beluga sturgeon is now critically endangered, according to the World Wildlife Fund.

The Volga River Delta in the North Caspian is home to a wide range of endemic or rare aquatic plants, according to the World Wildlife Fund. The vegetation in the Turkmenistan portion of the Caspian shores is considered impoverished. Nevertheless, there are some specialized salt-resistant plants like shrubs and sagebrush.

For more information, visit the website


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#66 2018-01-09 00:22:11

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

55) Six's Maximum and Minimum Thermometers

You may want to know what the highest (maximum) or lowest (minimum) temperatures have been in the last 24 hours. However you will not want to have to keep reading the thermometer, especially during the night. For this you will need to use a Six's thermometer. There are many sorts. This page tells you about some of them.

The bulb of the sixes thermometer in the Stevenson Screen should be approximately 1.2m (120cm) above the ground.

To see more different thermometers you can go to More About Temperature Readings or you may want to go back to the Temperature Readings page. Alternatively you may want to return to Collecting Data.

Six's Thermometer

The thermometer on the right is a special one for recording maximum and minimum temperatures. All Six's thermometers have one long 'U' shaped tube. This can be clearly seen in the image further down the page.

There is a bulb of alcohol at the top of the tube on the left. This cannot be seen on this thermometer. The alcohol expands or contract as the temperature changes. It then push round the indicator liquid to show the temperature. This example has no mercury, and is therefore safer.

You get to see the temperature twice, it should show the same temperature on both scales. Both Celsius scales show 19 °C.

The Marker Pins

So that the Maximum (hottest) and Minimum (coldest) temperatures can keep be recorded there are two small steel pins.

When the temperature rises, the marker 'pin' in the right hand column is moved. It will stay there until you reset it. You read the bottom of the 'pin'. This example is 28°C.

When the temperature falls, the marker in the left hand column will be moved to show the minimum temperature. Read the 'pin' at the bottom point.

Reading the Scales

The close-up of a part of the scales on the right shows how they are reversed.

The right hand scale, for the maximum temperature, is the 'normal' way up. The larger numbers are at the top. Below the zero are the minus numbers (shown here in red).

The left hand scale, for recording the minimum temperatures, is reversed. The larger numbers are at the bottom. The minus numbers are above the zero (see the plus and minus signs).

When reading the temperatures that the pins were left at, always start at the zero and look carefully whether the number should be a positive number or a negative number.

Caring for a Six's Thermometer

As with most weather instruments you need to treat a Six's thermometer very carefully. There are glass parts which can be easily broken. If any instrument gets broken seek advice from an adult immediately.

When you buy a Six's thermometer make sure that the indicator liquid does not have any gaps in it. Also check that the pins are not buried in the indicator liquid.
Although many Six's thermometers have mercury for the indicator liquid there are ones without this poisonous metal. You can see the shiny silver colour. It may be better to purchase one without mercury.

Error Checking

When you record your data from your sixes thermometers you will record three numbers. These are the maximum and minimum temperatures and the current temperature. The highest number will be the maximum, the lowest the minimum, and the current temperature will be somewhere in between. Once you have recorded the number take a moment to check that they are in the right boxes.

James Six (1731 - 1793)

This is called a Six's thermometer because it was invented by a man called James Six.He was born in Canterbury and did some scientific experiments in the cathedral.

As part of his science experiments he wanted to record the weather and did not want to keep getting up in the night to take readings. For this reason he invented this sort of maximum and minimum thermometer.

Why record Maximums and Minimums?

Most people love record breakers. If you only record the temperature when you are looking at your thermometer you might miss a record breaking temperature, either a maximum or a minimum. If you have a Sixes Thermometer, or a digital maximum and minimum thermometer you will record the highest and lowest temperature whatever time they occur.

There are some environments where it is important to know how hot or cold it is getting. In a greenhouse plants need particular conditions to grow. Monitoring the temperature will help plan caring for them. If the maximum temperature is too high some means of cooling the greenhouse down can be sorted out. If it is getting cold (perhaps in the middle of the night) a heater can be used. Monitoring conditions in many other places is also important; classrooms, hospitals, libraries, museums...

Recording this data over a period of time means that changes in the climate can be observed. Meteorologists look back into records from many years ago to see what is happening in the long term.

Please Note:
Please be conscious of any safety issues regarding these activities. It may be advisable to avoid any instruments which contain mercury.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#67 2018-01-11 00:30:49

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

56) Malic Acid

Malic acid is a component of many of the foods that we eat daily. Although it is found as a naturally occurring organic compound in various fruits, many choose to take malic acid supplements to increase their overall health, as well as treat various maladies. Today, the acid is most commonly used as a food additive and preservative. It is a mild and relatively harmless acid when used in appropriate amounts. As a food supplement, it is generally considered beneficial for health and is present in large amounts in apple juices. As when taking any supplement, however, you should not exceed the recommended amounts for consumption.

Benefits of Malic Acid

Pain Reduction

One of its most commonly touted benefits is its ability to help reduce pain. For this reason, it is frequently used by those who suffer from fibromyalgia and chronic fatigue system. Those who take it for this reason have reported reduced muscle soreness and pain. Although it takes several days of consistent consumption for the supplement to take full effect, it can start to reduce pain as quickly as 48 hours after your first supplement.

Energy Boost

In addition to providing reduced pain, it is also said to provide increased energy. This is another side effect enjoyed by sufferers of chronic fatigue syndrome and fibromyalgia. Those who have it as a supplement to their diet, especially those who suffer from these conditions, have experienced a significant reduction in fatigue, giving them a much-needed boost of energy.

Skin Care Benefits

Not only is this acid used in the form of a food supplement, it is also a common additive to skin care products. Malic acid has long been used in skin products for its exfoliating properties. Furthermore, it is able to penetrate the skin more deeply, due to its chemical composition. As a result, products that employ this great supplement can greatly help in improving skin smoothness, pigmentation and complexion. Its superior ability to penetrate the skin makes it an ideal moisturizer for people who have very sensitive skin that does not benefit form typical moisturizers.

In the majority of products it is used in, it functions largely as a pH adjuster. By raising the pH of the skin, this acid helps to facilitate healthy exfoliating, thereby improving the overall health and appearance of the area that you are targeting.

Side Effects

Although generally regarded as a very safe and effective supplement, there can be some minor side effects. The most common of these, while uncomfortable, are only experienced by a small number of those who use the supplement. The side effects most frequently experienced include muscle pain, nausea, redness, constipation, swollen skin, chest pain and itching. While annoying, these typically dissipate after a couple days.

While most of the side effects are relatively minor, there are also some more serious side effects, which are very rare. These serious side effects are often more serious forms of their minor counterparts, such as extreme chest tightness. This also includes dangerous events such as allergic reaction, which can lead to difficulty breathing or a completely closed throat. If you experience any of these, seek medical help immediately.

Foods Containing Malic Acid

The food that is most well known for its high malic acid content is the apple. Other fruits with a very high concentration of the acid are nectarines, cherries, lychees, bananas, mangoes, peaches, tomatoes and strawbesrries. It can be found, however, in nearly all fruits.

Malic acid is also used as a flavor enhancer for many drinks and candies. It is especially common in diet sodas and other artificially sweetened drinks. This is also true of artificially sweetened candies, such as gum and other gummy candies. Because of its highly versatile nature, especially in masking unnatural flavors, it has become an important part of nearly any food product that contains alternative sweeteners.

One of the greatest things about malic acid as both a food supplement and a skincare agent is the fact that it is a completely natural, organic compound. Rather than relying on man-made products to improve the health of your body and skin, it provides a natural alternative for a variety of purposes. Whether you are treating your chronic fatigue, fibromyalgia or just some dry skin, this acid is a safe and readily available solution. Because of its powerful pain relieving and healing properties, it has become a very popular, and viable solution for many people in the treatment of their various maladies. This has only been amplified by its overall safety.

DL-Malic Acid Background and Benefits

Malic acid is a dicarboxylic acid with the chemical formula C4H6O5, which has two structures known as enantiomers. L-malic acid occurs naturally in all organisms, while D-malic acid must be synthesized in the laboratory. A mixture of D-malic acid and L-malic acid is called a racemic mixture, which is commonly known as DL-malic acid.

The Swedish chemist Carl Wilhelm Scheele first isolated malic acid from apple juice in 1785. Its name comes from “malum,” which is the Latin word for apple. Malic acid is a major contributor to the sourness in apples, although its concentration decreases as the apple ripens. It is also the primary flavor in rhubarb and is used to flavor “salt and vinegar” potato chips.

L-malic acid is often formed in organisms as an intermediate product of metabolic reactions involving pyruvate. It also has many esters and salts known as malates that play critical biological roles. Malates are a source of carbon dioxide in the Calvin cycle, and they are also an intermediate product in the citric acid cycle. D-malic acid is primarily used in health supplements, typically in the form of DL-malic acid.

L-malic acid may be produced commercially by fermenting fumaric acid. Racemic malic acid is typically synthesized by double hydrating maleic anhydride.

Uses of DL-Malic Acid

The uses of DL-malic acid generally relate to the role of malic acid in the production of chemical energy for both aerobic and anaerobic conditions. These uses include the management of discomfort, energy production, oral hygiene and general detoxification.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#68 2018-01-13 16:48:10

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

57) The Grand Canyon

#1 The Grand Canyon reveals 40% of Earths history.

The Grand Canyon contains the metamorphic rock Vishnu schist, and layers of sedimentary rock that date back to 1.75 billion years old — that’s nearly half the age of the Earth  (4.5 billion years old)! That means there are tons of fossils and tracks to help us learn about ancient species.

#2 There are pink snakes!

There are six different types of rattlesnakes that call the Grand Canyon home but one of them sticks out a little more than the others. Or doesn’t stick out, actually, because the pink hue of the snake works as camouflage among the sunlit rocks.

#3 The Grand Canyon encompasses several ecosystems.

As you descend into the Grand Canyon, your surroundings can change rapidly. There are around 70 mammal species, 47 reptile species, 250 species of birds, and over 1,750 plant species. Temperatures have been recorded from -10° to 110° Fahrenheit in various locations of the canyon.

#4 The Grand Canyon is the reason we have the FFA.

Back in the 1950’s, the awe-inspiring view of the canyon was so tempting that there were numerous plane collisions resulting from pilots who decided to take a scenic detour away from their flight path. These tragedies necessitated the in-air regulations we have today, and they’re the reason that, these days, you can safely fly over the Grand Canyon for a unique view.

#5 The Pueblo Indians were the first to call the Grand Canyon home.

More than 3,000 years ago, the Grand Canyon worked well as as a place to provide shelter and store food. Not only this, but the Grand Canyon was believed to be a holy land. We continue to learn more about the Pueblo Indians today, as we find tools and structures that they left behind.

#6 The air at the Grand Canyon is some of the cleanest in the U.S.

As a National Park, the Grand Canyon is well protected. Barring the occasional dust storm or forest fire, chances are good that you’ll be breathing easy. It’s no wonder that over 5 million people a year come to experience this beautiful feat of nature.

#7 It’s still growing

Scientists generally agree that the Grand Canyon is a result of continual erosion by wind, rain, and the powerful Colorado river. The Colorado river still flows today, of course, which means that the Grand Canyon is constantly getting bigger and changing shape. It’s a slow process, but it’s happening nonetheless!

#8 People still live in the Grand Canyon, even today!

While you might think that the Grand Canyon is a beautiful place to visit, many people call this beautiful place home. Records show that some 2,000 people live in the Grand Canyon all year round. The majority of the inhabitants are members of the Havasupai Tribe, but we can’t forget those who keep Phantom Ranch (the only place to stay at the bottom of the canyon) up and running.

#9 Sometimes we start fires in the Grand Canyon on purpose!

This may seem like a destructive act against nature, but its goal is actually to prevent a tragedy. Firefighters strategically start small fires, called prescribed burns, that help refresh forest ecosystems and ensure that larger canopy fires don’t occur, resulting in widespread, tragic losses.

#10 The Grand Canyon is considered to be one of the 7 Wonders of the World.

On average, the canyon is 277 miles long, 18 miles wide, and 1 mile deep.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#69 2018-01-15 00:27:21

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

58) Universal Serial Bus

What does Universal Serial Bus (USB) mean?

A Universal Serial Bus (USB) is a common interface that enables communication between devices and a host controller such as a personal computer (PC). It connects peripheral devices such as digital cameras, mice, keyboards, printers, scanners, media devices, external hard drives and flash drives. Because of its wide variety of uses, including support for electrical power, the USB has replaced a wide range of interfaces like the parallel and serial port.

A USB is intended to enhance plug-and-play and allow hot swapping. Plug-and-play enables the operating system (OS) to spontaneously configure and discover a new peripheral device without having to restart the computer. As well, hot swapping allows removal and replacement of a new peripheral without having to reboot.

Although there are several types of USB connectors, the majority of USB cables are one of two types, type A and type B. The USB 2.0 standard is type A; it has a flat rectangle interface that inserts into a hub or USB host which transmits data and supplies power. A keyboard or mouse are common examples of a type A USB connector. A type B USB connector is square with slanted exterior corners. It is connected to an upstream port that uses a removable cable such as a printer. The type B connector also transmits data and supplies power. Some type B connectors do not have a data connection and are used only as a power connection.

The USB was co-invented and established by Ajay Bhatt, a computer architect who had been working for Intel. In 1994 seven companies that included Intel, Compaq, Microsoft, IBM, Digital Equipment Corporation (DEC), Nortel and NEC Corporation started the development of the USB. Their objective was to make it easier to connect peripheral devices to a PC and eliminate the mass amount of connectors. Factors involved included: creating larger bandwidths, streamlining software configurations and solving utilization problems for current interfaces.

The USB design is standardized by the USB Implementers Forum (USBIF) that is comprised of a group of companies supporting and promoting the USB. The USBIF not only markets the USB but maintains the specifications and upholds the compliance program. Specifications for the USB were created in 2005 with the 2.0 version. The standards were introduced by the USBIF in 2001; these included the older versions of 0.9, 1.0 and 1.1, which are backward compatible.

Universal Serial Bus (USB)

A Universal Serial Bus (USB) is basically a newer port that is used as a common interface to connect several different types of devices such as keyboards, printers, media devices, cameras, scanners, and mice. It is designed for easy installation, faster transfer rates, higher quality cabling and hot swapping. It has conclusively replaced the bulkier and slower serial and parallel ports.

One of the greatest features of the USB is hot swapping. This feature allows a device to be removed or replaced without the past prerequisite of rebooting and interrupting the system. Older ports required that a PC be restarted when adding or removing a new device. Rebooting allowed the device to be reconfigured and prevented electrostatic discharge (ESD), an unwanted electrical current capable of causing serious damage to sensitive electronic equipment such as integrated circuits. Hot swapping is fault tolerant, i.e. able to continue operating despite a hardware failure. However, care should be taken when hot swapping certain devices such as a camera; damage can occur to the port, camera or other devices if a single pin is accidently shorted.

Another USB feature is the use of direct current (DC). In fact, several devises use a USB power line to connect to DC current and do not transfer data. Example devices using a USB connector only for DC current include a set of speakers, an audio jack and power devices like a miniature refrigerator, coffee cup warmer or keyboard lamp.

USB Version 1 allowed for two speeds: 1.5 Mb/s (megabits per second) and 12 Mb/s, which work well for slow I/O devices. USB Version 2 allows up to 480 Mb/s and is backward compatible with slower USB devices. USB supports three.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#70 2018-01-17 00:28:43

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

59) Parkinson's Disease


Parkinson's disease is a progressive disorder of the nervous system that affects movement. It develops gradually, sometimes starting with a barely noticeable tremor in just one hand. But while a tremor may be the most well-known sign of Parkinson's disease, the disorder also commonly causes stiffness or slowing of movement.

In the early stages of Parkinson's disease, your face may show little or no expression, or your arms may not swing when you walk. Your speech may become soft or slurred. Parkinson's disease symptoms worsen as your condition progresses over time.

Although Parkinson's disease can't be cured, medications may markedly improve your symptoms. In occasional cases, your doctor may suggest surgery to regulate certain regions of your brain and improve your symptoms.


Parkinson's disease symptoms and signs may vary from person to person. Early signs may be mild and may go unnoticed. Symptoms often begin on one side of your body and usually remain worse on that side, even after symptoms begin to affect both sides.

Parkinson's signs and symptoms may include:

Tremor. A tremor, or shaking, usually begins in a limb, often your hand or fingers. You may notice a back-and-forth rubbing of your thumb and forefinger, known as a pill-rolling tremor. One characteristic of Parkinson's disease is a tremor of your hand when it is relaxed (at rest).
Slowed movement (bradykinesia). Over time, Parkinson's disease may reduce your ability to move and slow your movement, making simple tasks difficult and time-consuming. Your steps may become shorter when you walk, or you may find it difficult to get out of a chair. Also, you may drag your feet as you try to walk, making it difficult to move.

Rigid muscles. Muscle stiffness may occur in any part of your body. The stiff muscles can limit your range of motion and cause you pain.
Impaired posture and balance. Your posture may become stooped, or you may have balance problems as a result of Parkinson's disease.
Loss of automatic movements. In Parkinson's disease, you may have a decreased ability to perform unconscious movements, including blinking, smiling or swinging your arms when you walk.

Speech changes. You may have speech problems as a result of Parkinson's disease. You may speak softly, quickly, slur or hesitate before talking. Your speech may be more of a monotone rather than with the usual inflections.

Writing changes. It may become hard to write, and your writing may appear small.

When to see a doctor

See your doctor if you have any of the symptoms associated with Parkinson's disease — not only to diagnose your condition but also to rule out other causes for your symptoms.


In Parkinson's disease, certain nerve cells (neurons) in the brain gradually break down or die. Many of the symptoms are due to a loss of neurons that produce a chemical messenger in your brain called dopamine. When dopamine levels decrease, it causes abnormal brain activity, leading to signs of Parkinson's disease.

The cause of Parkinson's disease is unknown, but several factors appear to play a role, including:

Your genes. Researchers have identified specific genetic mutations that can cause Parkinson's disease, but these are uncommon except in rare cases with many family members affected by Parkinson's disease.

However, certain gene variations appear to increase the risk of Parkinson's disease but with a relatively small risk of Parkinson's disease for each of these genetic markers.

Environmental triggers. Exposure to certain toxins or environmental factors may increase the risk of later Parkinson's disease, but the risk is relatively small.
Researchers have also noted that many changes occur in the brains of people with Parkinson's disease, although it's not clear why these changes occur. These changes include:

The presence of Lewy bodies. Clumps of specific substances within brain cells are microscopic markers of Parkinson's disease. These are called Lewy bodies, and researchers believe these Lewy bodies hold an important clue to the cause of Parkinson's disease.

Alpha-synuclein is found within Lewy bodies. Although many substances are found within Lewy bodies, scientists believe an important one is the natural and widespread protein called alpha-synuclein (A-synuclein). It's found in all Lewy bodies in a clumped form that cells can't break down. This is currently an important focus among Parkinson's disease researchers.

Risk factors

Risk factors for Parkinson's disease include:

Age. Young adults rarely experience Parkinson's disease. It ordinarily begins in middle or late life, and the risk increases with age. People usually develop the disease around age 60 or older.

Heredity. Having a close relative with Parkinson's disease increases the chances that you'll develop the disease. However, your risks are still small unless you have many relatives in your family with Parkinson's disease.

Physical relation.

Men are more likely to develop Parkinson's disease than are women.

Exposure to toxins. Ongoing exposure to herbicides and pesticides may put you at a slightly increased risk of Parkinson's disease.


Parkinson's disease is often accompanied by these additional problems, which may be treatable:

Thinking difficulties. You may experience cognitive problems (dementia) and thinking difficulties, which usually occur in the later stages of Parkinson's disease. Such cognitive problems aren't very responsive to medications.

Depression and emotional changes.

People with Parkinson's disease may experience depression. Receiving treatment for depression can make it easier to handle the other challenges of Parkinson's disease.

You may also experience other emotional changes, such as fear, anxiety or loss of motivation. Doctors may give you medications to treat these symptoms.

Swallowing problems.

You may develop difficulties with swallowing as your condition progresses. Saliva may accumulate in your mouth due to slowed swallowing, leading to drooling.

Sleep problems and sleep disorders.

People with Parkinson's disease often have sleep problems, including waking up frequently throughout the night, waking up early or falling asleep during the day.

People may also experience rapid eye movement sleep behavior disorder, which involves acting out your dreams. Medications may help your sleep problems.

Bladder problems. Parkinson's disease may cause bladder problems, including being unable to control urine or having difficulty urinating.


Many people with Parkinson's disease develop constipation, mainly due to a slower digestive tract.

You may also experience:

i) Blood pressure changes. You may feel dizzy or lightheaded when you stand due to a sudden drop in blood pressure (orthostatic hypotension).
ii) Smell dysfunction. You may experience problems with your sense of smell. You may have difficulty identifying certain odors or the difference between odors.
iii) Fatigue. Many people with Parkinson's disease lose energy and experience fatigue, and the cause isn't always known.
iv) Pain. Many people with Parkinson's disease experience pain, either in specific areas of their bodies or throughout their bodies.
v) Physical dysfunction. Some people with Parkinson's disease notice a decrease in physical desire or performance.


Because the cause of Parkinson's is unknown, proven ways to prevent the disease also remain a mystery. However, some research has shown that caffeine — which is found in coffee, tea and cola — may reduce the risk of developing Parkinson's disease. Green tea also may reduce the risk of developing Parkinson's disease.

Some research has shown that regular aerobic exercise may reduce the risk of Parkinson's disease.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


#71 Yesterday 00:59:47

Registered: 2005-06-28
Posts: 23,579

Re: Miscellany

60) Search Engine

A search engine is a software program or script available through the Internet that searches documents and files for keywords and returns the results of any files containing those keywords. Today, there are thousands of different search engines available on the Internet, each with their own abilities and features. The first search engine ever developed is considered Archie, which was used to search for FTP files and the first text-based search engine is considered Veronica. Today, the most popular and well-known search engine is Google. Other popular search engines include AOL,, Baidu, Bing and Yahoo.

How to access a search engine

For users, a search engine is accessed through a browser on their computer, smartphone, tablet, or another device. Today, most new browsers use an Omnibox, which is a text box at the top of the browser that shows the address and is where you can also search on the Internet. You can also visit one of the major search engines home page to perform a search.

How a search engine works

Because large search engines contain millions and sometimes billions of pages, many search engines not only just search the pages but also display the results depending upon their importance. This importance is commonly determined by using various algorithms.

Visual search engine exampleAs illustrated in the image on the right, the source of all search engine data is a spider or crawler, which automatically visits pages and indexes their contents.

Once a page has been crawled, the data contained within the page is processed and indexed. Often, this can involve the steps below.

Strip out stop words.
Record the remaining words in the page and the frequency they occur.
Record links to other pages.
Record information about images or other embedded media.

The data collected above is used to rank the page and is the primary method a search engine uses to determine if a page should be shown and in what order.

Finally, once the data is processed it is broken up into one or more files, moved to different computers, or loaded into memory where it can be accessed when a search is performed.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


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