Thursday, 14 November 2019
Wednesday, 13 November 2019
Why is the water of Sea Blue?
Why is Sea Blue? This is a very odd thing because the sea is also wet and spread out under the sun. It ought to be green with plants as is the land, but it is not. There are murky coasts and estuaries, the green hard waters of stormy channels, the fog-covered silvery- grey of ocean banks. But the deep sea, the open sea, most of the sea, is blue. This strange blueness of the sea can tell us many things.
An explanation for the color of the sea is simple enough. There are not enough plants in the sea to make it green, so we are left with the color of pure water under the sun. The light that passes through perfectly clear water is absorbed bit by bit, it's the energy dissipated as heat as it travels until at last all of it has flowed into the sink of heat and there is utter blackness.
But the colors of white light go progressively, one at a time. The low-energy wavelengths that we call “red” go first, then, in turn, the more intense parts of the spectrum orange, yellow, green and finally the various shades of blue. Only blue light reaches a few hundred feet down, and it follows that any reflected light that has made a double journey from the surface to the depths and back is blue. And so, the sea is blue.
But the real reason that the sea is blue is that there are not enough plants in it to make it green. And this is one of the oddest of the odd things about our world. Why are the great oceans not green with plants? We can get a first hint of where to look for our answer by reflecting on those few places in the sea that in fact are green, the shallow banks such as the Dogger Bank or regions of great upwellings such as those on the Peruvian coast.
These are the sites of the great fisheries, and the waters are murky green with plant life. The fisheries themselves attest to the rich productive qualities of these scattered places, and the green murk bespeaks high fertility. Indeed, high fertility, in the simple chemical sense, is the explanation of both the fisheries and the green murk.
The waters of banks and upwellings are well-supplied with chemical nutrients so that the tiny planktonic plants of the sea thrive abundantly, turning the water into a green soup in which animals wallow, to the eventual well-being of fishermen.
Where the sea is unusually fertile, tiny plants multiply and the water becomes green with their bodies. But most of the sea is not fertile; it is a chemical desert. Potassium, phosphorus, silicon, iron, nitrates and the rest are always present in sea-water, but in low concentrations.
By the standards of agriculture, the open sea is hopelessly infertile. And if the sea is infertile it is perhaps not unreasonable to expect that plants will not grow there very well, which is presumably why there are so few of them.
So far, we seem on safe ground, but there is a very large catch to the argument. Everything depends on the fact that the plants of the sea are tiny. In very fertile water (a polluted estuary is the best example) the tiny plants multiply until the water is pea-green with their bodies.
But if the water is a nutrient-poor desert like the great oceans, then there are only enough chemicals in the lighted upper layers of the sea to make a very few plants cells. The water is then essentially empty, the sun plunges down to the depths, and the water glows blue. But all these only follows//the plants are tiny.
Suppose there were large plants floating on the surface of the sea, plants that covered it with layers of leaves as the rain-forest trees cover the tropical land. These large plants would not have to worry about the thin supply of nutrients in the water any more than the rain-forest trees of the last chapter are stopped by the even thinner supply in the red tropical soils.
Large plants can collect, accumulate, and hoard nutrients. How easy it ought to be for a large plant in the sea. Deep down below the lighted surface of the sea, there are, in fact, almost unlimited nutrients, for the great oceans are some five miles deep in the middle. The fertilizer problem is one of concentration. In the few tens of meters at the top of the ocean, where the light reaches, and the plants must grow.
Hence, there is a local shortage of nutrients, but the potential supply underneath is truly enormous. A large plant at the surface would soak up nutrients, just like a large plant on land. More nutrients would then diffuse up from the depths to be similarly collected. And so on. Thus, if there were large plants in the open sea, the dilution of nutrients would not matter.
Now our inquiry comes close to Darwinian realities. The sea is blue, not so much because it is infertile but because there are no large plants growing there. Large plants would overcome the infertility of the surface water by gradually collecting nutrients as they filtered up from the depths below.
Large plants would become the dominant factor in the life of the sea as they are of the life of the land, making a massive shade of the spaces below them, forcing all food chains of animals to start with types that could bite out chunks from foliage. But no large plants live in the open sea. They can grow around coasts as do the kelps.
The giant kelps of the American Pacific, Macrocystis and Nereocystis, are said to be the longest vegetables in the world. But none of these large sea plants makes it out to a floating life in the open sea. For some reason, the niche or profession of “large-planting” is not possible in the open sea. Why? This is the fundamental Darwinian question behind the blueness of the sea.
Oceanographers have long known that there is something odd about the absence of big plants from the sea, but they have missed the grand Darwinian question. They never asked themselves, “Why can’t the plants be big?” Instead, they looked for the advantages of being small, counting the blessings of smallness and expecting to find their answers in this way. But you cannot get all of the answer like that.
Consider some of the so-called advantages of being small, particularly those based on the surface area. A small object has a much larger surface in proportion to its volume or mass than a big one. One result of this is less trouble with the sinking-problem, since the relatively large surface offers more friction, slowing the sinking rate. On the other hand, if you have a bladder of air or oil, you do not sink at all, so why bother being small?
Another is that the large surface to your little body can be used to soak up scarce nutrients. But there are ways of having a large surface area other than being tiny; by being convoluted or sponge-like, for instance. Rain-forest trees manage with a mat of hairs, even in mud and gravel let alone water. A spongy giant of an ocean plant would find soaking up nutrients easy; then it would be able to hoard its nutrients even as land vegetation does.
I have read in an oceanographic text that small entities use nutrients “efficiently.” This means that “turnover” is efficient if one thinks of the oceans as a banker thinks of a company that “turns over“ its capital quickly. But it is a strange sort of efficiency that keeps the oceans as a poorly productive desert.
If the ocean plants were large, they would soak up nutrients from below and make the ocean desert bloom like the lowland tropics. The “efficiency” of production would then be much greater. So why be small?
There must be some the advantage in being small, and we can best find what it is by looking for the the disadvantage of being big in the sea and whatever this disadvantage might be it surely must be overriding. There are big plants everywhere else, on all kinds of land surfaces and in every shallow patch of the sea along its coasts. It is only in the open sea, where they would have to float that there are no big plants. So, the answer to the problem must lie in a floating way of life.
Why do small plants make a success of floating in the sea whereas big ones do not? The answer stares us in the face. If a plant floats, it drifts, and if it drifts, it is soon blown away from where it wants to be. There must be some way to get back. A big floating mass kept up by air bladders or oil floats would never make it home after the first storm or the constant push of current had taken it away.
But it is easy to imagine ways in which tiny plants might arrange for their returns. The most obvious way is by letting themselves sink because the surface of the ocean is always being stirred. Water always moves into a patch of the sea as fast as water is taken away and for every leaving current there must be a current returning.
It seems likely that small plants can thrive in the open sea by following the currents round. It is possible, too, that they disperse in the air as well, being kicked out of the waves in spray and blown about the world oceans. Tiny plants can ride the currents to stay in home waters or travel the oceans to get back there. Large floating masses of vegetation cannot.
So, final hypothesis to explain the blueness of the sea is that large plants are excluded from it not by short commons in nutrients, but by the restless motion of the waters that would sweep them all away never to return. As it happens, fate has provided one intriguing test for the hypothesis in that there is one place in our contemporary ocean from which floating things are not swept away: the Sargasso Sea.
The Sargasso is at the center of a slow but enormous gyre, an oceanic whirlpool that gathers floating debris to its middle. This was so dangerous an area for sailing ships that legends have grown of ancient vessels, trapped by the remorseless swirling waters, rotting together far out in the Atlantic.
Columbus had his own grim meeting with the Sargasso, saving himself from the mutinous temper of his crew only by scooping a crab off the weed that floated alongside and claiming that the weed with its crab meant that land was near. But the land was a long way yet. The weed was the big floating brown alga we call Sargassum, and it floated thickly over the surface of the Sargasso Sea because the gyre held its population in place.
Sargasso weed floating about as straggling fragments can be found in many of the world’s oceans as can fragments of other species, oiFucus, and Ascophyllum, of any of the anchored coastal plants that bear floats and that might be tom up by storms. These floating fragments survive for a while as they drift, but they are all doomed.
They are not adapted to oceanic life; they cannot reproduce as they float about; they leave no offspring; and they die. But in the Sargasso Sea things are different. There the local species of Sargassum lives its whole life, reproducing, and persisting generation after generation.
Evidently this gyre in the oceans has persisted long enough for natural selection to produce from the chance debris of floating coastal algae a species able to carry on its life cycle as it floats. And the plant has done this in a patch of water notoriously unproductive in the sense of holding few nutrients.
The story of the sargasso weed leads us to believe that where it is possible for floating plants to stay put in the sea, we shall find large, floating plants. That we do not find them all over the oceans is because the oceans do not keep still. Natural selection then forces extreme smallness on the plants that are there, for the tiny ones are those best able to disperse about the seas.
If the surface waters are provided by conveyor-currents of nutrients in upwellings, or run-off from the land, or with delicious rivers of garbage like those that pour from the The Tiber, the Hudson, or the Medway, then the tiny plants will so multiply that the blue of the ocean is banished, and a green or turbid murk tells of vibrant life.
But if the sea is a nutrient-poor desert, like most of the world's oceans, then the tiny plants cannot be very numerous. There is then neither a canopy of floating vegetation nor a soup of tiny algae. Sunlight plunges deep into the water, it's fewer intensive rays being rapidly extinguished the while. Only the shorter wavelengths make the double journey to and from the depths. Which is why the sea is blue.
Reference: Paul Colinvaux
Why is Sea Blue? This is odd thing because sea is wet & spread out under the sun. It ought to be green with plants as the land but it is not.
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Thursday, 30 August 2018
Why Do We Grow Old?
Why Do We Grow Old? This question
often comes in mind, but no one has right answer. When Friends meet
after the passage of some years they probably remark, inwardly or
outspokenly. How time has altered the appearance if each. In the
ordinary way, people are not aware of growing older.
It is that sort of meeting that
makes them conscious of it. In each human body, physical and
psychological changes occur with increasing years. And a combination of a
number of these changes indicates the approach or presence of old age.
From about the age of 21 we begin to grow old. What causes; the gradual
changes, both external and inside the body. Which eventually lead to old
age?
Can Anything be Done to Delay this Process of Why Do We Grow Old?
The most familiar changes relate to
the external appearance of the body. The skin loses its elasticity and
bloom, becoming folded and wrinkled and flabby. The hair loses its
original color, becoming grey. Actual hair loss, producing baldness,
occurs more especially in men but also in women.
The muscles of the limbs and trunk
become weaker and thinner. It is causing a general appearance of weight
loss, while the bony parts of the skeleton become less dense with a
greater tendency to fracture. Wear and tear thins the discs between the
vertebrae of the spine, producing some shortening of stature.
The difference between three
generations of women is expressed not only in physical appearance but in
posture and style of dress.
- A stooping posture, dim, sunken eyes, a wrinkled skin, grizzled hair and beard such signs of age imprinted by a lifetime’s experience nevertheless impart character to this head.
- An elderly German obviously has no intention of resigning himself yet to becoming a mere spectator at the sports festival.
- An old French woman concentrates on her knitting. Though the joints may become stiff with age, long experience can make old people very quick and deft at performing manual tasks. Poor muscle tone also make an old person appeal shorter. A protruding abdomen or paunch may result both from lack of tone in the voluntary muscles and excess fat in the abdominal wall.
- Facial appearance may be altered both by changes in the sheen of the skin and by wrinkles but also by the presence of dentures replacing decayed teeth. The individual’s own teeth may have been affected by dietary habits and dental attention, but age does thicken the teeth, producing a yellow appearance.
Glasses and Hearing Aids
Hearing aids and glasses are clues
to the fact that the senses are also affected by ageing. Changes in the
inner ear lead to a gradual loss of high tone hearing, making group
conversation difficult to follow. Whether a person is long sighted,
short sighted or normal sighted in younger years, advancing age alters
the eye lens and lens muscles.
This causes increasing difficulty in
reading small print, calling for correction by suitable glasses.
Sharpness of vision and night vision may also decrease because of age
changes in the light-sensitive cells in the retina at the back of the
eye.
The other senses of taste, smell,
touch and vibration become less efficient over the years but are never
completely lost unless disease of the nervous system supervenes. The
sense of pain is usually retained in old age, though its messages may
not be interpreted so efficiently by the brain.
Professional singers and political
orators become aware sooner than most that age affects the strength and
range and timbre of the voice. Thinning or the muscles of the voice box
and loss of tissue in its cartilages helps produce the change in voice.
Which may the universally felt dread
of old age finds harsh expression in a typically brutal caricature. Two
old people drinking soup become hoarse or high and piping. Dentures or
lack of teeth may also result in slurred speech. While brain changes can
affect what is said and slow the delivery.
Changes inside the body may be less
obvious but continue apace with advancing years. The linings of the
joints, particularly the weight-bearing joints like knees and hips, are
subject to wear and tear. This reduces the mobility of the joints, which
become stiffer, affecting walking and other movements.
In the digestive system there is
thinning of the stomach lining. But this has little influence on actual
digestion unless disease is present as well. Sometimes there is reduced
secretion of enzymes from the salivary glands and the pancreas, which
does interfere with digestion.
The kidneys produce urine normally
in old age, excreting the body’s waste products satisfactorily. There is
some gradual decline in the kidneys’ reserve function though, and the
old are vulnerable to any sharp decline in water intake. Such as may
occur in a debilitated old person living alone and neglecting diet and
fluid for some time.
With age, breathing becomes less
efficient, partly due to changes in lung capacity through loss of
elasticity. There may be thinning of the heart muscle with advancing
years and an associated reduction in working capacity. The actual heart
rate may be the same as in younger people or it may slow up, and there
is a greater tendency to irregular beats.
The shuffling or unsteady gait noted
when old people move about is one result of impaired co-ordination due
to changes in the 130 nervous system. This may he made worse by muscle
weakness and lack of tone and further exaggerated by disease.
In the female human body, the
ovaries cease to function at the menopause around the end of the fourth
decade of life. In the male human body, however, the testicles can
continue to function well into the seventh and even eighth decade.
This means that women cease to be
able to reproduce in middle age while men can continue to father
children into old age. In both sexes there is a gradual but steady
decline in sexual activity but the sexual urge can be well maintained
into old age.
Living in the past
The
overall physical picture of ageing in the human body is therefore one
of a general decline in vigor, in activity and in organ function.
Moreover, old people respond badly to extremes of external temperature
in particular, thin skin, poor muscle-shivering reflex and slower
blood-vessel contraction in the skin make them less able to tolerate
cold.
Contrary to popular notions, there is no thinning of the actual blood with age. Where there is lack of blood it is caused by dietary deficiency or disease. Changes in mental powers have recently been studied more fully. Mental alertness and fitness may be well preserved into later years.
There is a gradual and cumulative
deterioration in intellectual function as age advances. However
particularly with respect to new situations new ideas and new techniques
involving co-ordination and the power to adapt. The decline in memory
affects learned facts and recently occurring events especially, while
past incidents are well recalled. Artistic creativity is also likely to
fall off.
An important change in the
blood-vessels, known as arteriosclerosis (popularly called ‘hardening of
the arteries.), affects everyone as he grows older. The normally
elastic and supple arteries become narrowed rigid and twisted. As a
result the oxygen supply to the tissues through the blood is reduced and
degeneration and ultimate decay of cells. Tissues and organs ensues.
The actual age of onset of
arteriosclerosis is variable, some people may be affected in early
middle age. The severity of the condition also varies some people may be
affected more than others. Such factors as the presence of high
blood-pressure, or sugar diabetes are known to encourage the earlier
development of arteriosclerosis. When arteriosclerosis is associated
with etheroma degeneration of the inner lining of the arteries – it is
called atherosclerosis.
Doctors and scientists alike have
argued whether arteriosclerosis is a normal biological ageing process or
whether it is due to ill-understood disease factors. General opinion
favors the latter concept. And so further research may enlighten us on
its cause and treatment. What is certain, however, is that
arteriosclerosis speeds up normal tissue decay by depriving the ageing
tissues of an adequate blood and oxygen supply. This is especially true
in the case of the brain and heart.
While insurance companies can
calculate the expectation of life at birth for men and women,
calculation of the rate at which an individual ages overall is very
difficult. Different tissues and organs age at different rates in each
human body, and the rate of ageing of individual organs or the body as a
whole may in addition be altered by stress, disease, arteriosclerosis
or uncertain factors like radiation.
Looked at in biological terms, the
human body has several growth periods up to puberty. Followed by further
development in adolescence until the full peak is reached at the age of
21. At that age, for example, long-bone growth ceases and many consider
that true ageing begins shortly after this time. Since the expectation
of life at birth is around 68 years for men and 72 years for women. It
follows that men and women have a very long ageing period.
The social, cultural and
evolutionary value of this long-ageing period is immense. It allows
individuals to organize their lives in terms of studying and training
for different occupations. Then developing the knowledge and expertise
thus gained in their employment over many years. It allows the growth of
cultural group patterns – secular, ethnic and religious and long
periods of individual cultural attainment.
Moreover, it gives adequate time for
the development of social and sexual relationships, and consequently of
family units as the essence of stable societies. In an evolutionary
sense, wisents and grandparents are themselves it means that the
children born to parents potentially long-living. The maximum at
different periods in their lives will vary, human life wins, and we have
seen is about producing genetic mutation and adaptation.
Very few animals apart from turtles
which regulates length of life, however the bio tortoises, have a life
span greater than the logical time clock’. It appears to be built in 110
years which is the usually accepted genetically. When the individual
contribution are upper limit for a human being and many Man’s
evolutionary plan of pro-familiar animals, like dogs and horses, grass
is over, ageing and death arrive.
Have a life expectancy of less than a
third the improvement in the average expected the three score years and
ten which is the portion of life from 60 years in 1930 to over. There
appears to be no single main genes but to an environmental change the
cause of human ageing. What seems to better medical and surgical
treatment of happen is that a number of factors – disease and better
social and economic inherited physical, chemical, psycho conditions?
Logical and environmental varying
with there are several cellular theories of each individual – cumulate
to damage and ageing to explain some of the tissue and ultimately
destroy the cells and tissues. Organ changes already described. The end
result of ageing is therefore cells are capable of dividing indefinitely
inevitably death of the individual as a throughout life, the old cells
being shed as whole.
The nature of these ageing factors
scales while the new one, replace them it is understood in some
instances and still is known by analogy with what happen to the subject
of research in others. In cancer, that this capacity for dividing
Heredity appears to influence the in and renewing can be altered both by
dividable life span.
1 At nearly 90 years of age the many people retained his extraordinary vitality, creativity and influence in their profession.
2 In the stress-free atmosphere of a
rural immunity people may live to great ages. Accepted as a member of
society with an active part to play, this old Turkish farmer still finds
life good.
3 In old age there is some
stiffening of the limbs, allied with an insecurity in balance and
greater tendency to fall, which makes getting downstairs a hazardous
business needing help.
1 and 2 A full, strenuous and
momentous life has been responsible for the difference taken at the
beginning and end of any career.
3 Men can continue to father
children until late in life, and they are more like than women to marry
partners much younger than themselves. The ever-youthful film actor Care
Grant became a father for the first time at the age of 62.X-rays in the
case of the skin and by chance mutations.
As a result the new cells produced
by the ageing human during the division process are progressively
inexact copies of their predecessors, and their function is
progressively less satisfactory. Cells of the central nervous system are
unable to regenerate at all, and once lost at any time throughout life
are irreplaceable. Ageing of the brain and spinal cord can be thought of
as progressive loss of cells through ill health, infection or changes
in the blood supply.
A current theory of ageing is
derived from speculation about certain types of illness such as thyroids
and acquired hemolytic anemia. In these illnesses it is believed that
the body’s ability to distinguish its own tissues from foreign invaders
of the body, zilch as micro- organisms, is disturbed.
The breakdown in the
self-recognition mechanism results the production of antibodies rich at
ac the body’s own proteins. In tie diseases mentioned, is responsible
for the destruction of thyroid-gland tissue and blood-cell tissue. It is
thought that this auto-immune process could operate in ageing as well
as in cases of specific disease, gradual degeneration steadily extending
throughout the body.
The fact that a woman’s expectation of life is greater by at least four years than a man’s has led to a suggestion that sex hormones have an effect on ageing. While there is some evidence that giving sex one to patients with chemical measurable sex-hormone deficiency, makes them look younger.
It does not altogether fundamental
ageing process. Similarly, illnesses caused by hormone deficiency, like
hypothyroidism. Which produce illness with the features of old age, are
corrected by giving in this case thyroxin hormone, but do not alter the
basic ageing tendency.
An older idea, based on animal
experiments, relates the body’s metabolic act it sits or rate of living,
to the speed of the ageing process. Metabolism is related to hormone
function and also to temperature levels and diet. A famous experiment
with rat-showed that these creatures could be retarded in their growth
and development by persistent low-calorie feeding, and that they lives
could be abnormally prolonged in this way. This does not mean.
However, that human ageing can be
retarded in the same way; although the converse is true overeating
leading to obesity shortens life. There is no clear evidence that human
ageing is affected by temperature. Extremes of temperature however, act
as a stress factor adapted to them and stress is thought it to influence
ageing. Stress, pain, privation, and neglect may because of premature
ageing. Which is promoted by arteriosclerosis has noted earlier.
As young as you feel the influence
of the mind on ageing is now being increasingly recognized. Apart from
the problems of adapting to the physical changes brought by age, such
causes of emotional disturbance as compulsory retirement from work,
bereavement, altered social role and economic anxiety may all contribute
to ageing. The absence of a positive function in old age can affect the
will to live and may accelerate the ageing process towards death.
From earliest times, Man has dreamed
of reversing the ageing process. Particularly with a view to sexual
rejuvenation, and of prolonging life indefinitely. The search for an
elixir of life by the medieval alchemists is one example of this
preoccupation.
The modern science of gerontology
studies the processes of ageing in animals and humans in order to
understand the difference between normal and disease-induced ageing. The
purpose is to determine the causes of normal ageing, and to see whether
the ageing processes can be retarded.
There has been no real progress in
the last-mentioned aim. Despite the widespread and uncritical use of so
called ‘anti-ageing’ drugs usually sex hormones, vitamins or procaine
derivatives no evidence of prolongation of the natural life span is
forthcoming.
The only real improvement has been in the care and rehabilitation of the sick or disabled old person. Nevertheless, some American enthusiasts are so sure of the success of gerontology that they are considering suspended and by a ‘deep freeze process called. Source: CP
Friday, 19 January 2018
Forget concussions. The real risk of CTE comes from repeated hits to the head, study shows
For more than a decade, researchers trying to make sense of the mysterious degenerative brain disease afflicting football players and other contact-sport athletes have focused on the threat posed by concussions. But new research suggests that attention was misguided. Instead of concerning themselves with the dramatic collisions that cause players to become dizzy, disoriented or even lose consciousness, neuroscientists should be paying attention to routine hits to the head, according to a study that examines the root cause of chronic traumatic encephalopathy, better known as CTE.
“On the football field, we’re paying attention to the bright, shiny object — concussion — because it’s obvious,” said Dr. Lee E. Goldstein of Boston University, who led the study published Thursday in the journal Brain. But, he continued, “it’s hits to the head that cause CTE.” The disease is marked by abnormal deposits of calcium and proteins throughout the brain, as well as by neuropsychiatric symptoms that range from tremors and memory problems to depression and suicidal rage. For now, the only way to diagnose it is by examining a patient’s brain tissue after death. Some of the hits that cause CTE may result in concussion, Goldstein said. But his team’s findings show that concussion is not necessary to trigger the process. Indeed, the new research suggests that concussion and CTE are completely different medical problems.
In mice, head impacts that caused concussion and those that led to CTE had different effects inside the brain. In people, the symptoms tend to show up as different behaviors that became evident at very different times. In mice, the research documented immediate behavioral responses to head impact that ranged from zero to disability. And researchers captured what appeared to be the earliest moments of CTE in many mice that showed few if any immediate symptoms. That new research underscores that the kinds of “sub-concussive” blows to the head that many athletes routinely endure are far more worrisome than players, their parents and their physicians have been led to believe. Even as football programs from Pop Warner to the National Football League are adjusting their rules to reduce concussions, the findings suggest these efforts will not be enough to prevent long-term injury.
”You have to prevent head impact,” Goldstein said. The new work originated at Boston University’s Center for Chronic Traumatic Encephalopathy and drew in dozens of experts from a wide range of disciplines and institutions. The team began by inspecting the brains of four teenage athletes who died one day, two days, 10 days and four months after suffering serious head injuries. Those brains were compared with others belonging to teen athletes who died without a history of head injury. The researchers observed an abnormal buildup of a protein called tau — a hallmark of CTE — in two of the athletes who experienced head trauma. One, in fact, met the diagnostic criteria for early CTE.
That and other evidence led the researchers to hypothesize that early CTE may result from leaky blood vessels in the brain. In the deep recesses of the organ’s folds, these damaged blood vessels were letting proteins spill into nearby brain tissue, triggering inflammation, they surmised. To see whether they were right, they needed to study a population of subjects with greater rigor. So they built a machine to deliver calibrated blows to young male mice, subjecting them to a range of head impacts. The effects of these blows were recorded in imaging scanners, in test mazes and on pathology slides.
The researchers examined the animals’ brain chemistry, cortical structure and behavior. Finally, they performed computer simulations to repeat and extend their findings on how various brain tissues responded to head impacts. The results were all over the map. Delivered a powerful blow, some mice would reel from the injury for days but then recover. Upon dissection, their brains might even look fine. Other mice, including many who got a series of blows equivalent to participating in a single game or practice, would behave normally in the days following a head impact. But not much later, their brains would reveal early signs of tau protein accumulations.
Sure enough, these deposits appeared to start in the deep recesses of the brain’s folds, where the hallmarks of full-fledged CTE are most clearly seen in humans too. The results may explain why approximately 20% of athletes who were found to have CTE after they died had never received a concussion diagnosis when they were alive, Goldstein said. And they suggest that people who seem to bounce right back after getting their “bell rung” may well have sustained damage that will not be evident for years.
“The overwhelming majority of people whose brains are hurt are going right back in and doing the worst thing possible: getting hit again and again,” Goldstein said.The research was presented in New York City in conjunction with a new campaign from the Concussion Legacy Foundation to discourage the participation of kids under 14 in tackle football. Goldstein and foundation cofounder Chris Nowinski said that playing flag football before the age 14 would reduce injuries to young players while allowing them to learn the game’s fundamentals. They were flanked by NFL Hall of Famers Nick Buoniconti and Harry Carson and Oakland Raiders legend Phil Villapiano. Nowinski, a former professional wrestler who is now a neuroscientist at Boston University, noted that the U.S. Soccer Federation forbids kids younger than 11 from heading the ball, and that USA Hockey outlawed checking in the sport for kids younger than 13. Youth football leagues should follow that trend, he said.“Football has been open season on your child’s head from the time they’re allowed to play,” said Nowinski, who was an award-winning defensive tackle during his college days at Harvard.
Goldstein agreed. “We should be paying attention to all hits,” he said. “And in kids, all the hits should be no hits.” For some parents and coaches, that may be difficult to imagine. But studies like the one published Thursday should help drive the message home.
“Football coaches are coaching these kids to help them,” Nowinski said. “Their hearts are in right place. They just need to be educated about what scientists are finding. This is really preserving the future for football.”Tuesday, 12 December 2017
Starwatch: A Dazzling Year for the Geminids
The reliable Geminids meteor shower has returned to our sky and, with the Moon as an unobtrusive waning crescent before dawn, we are in for a spectacular display of meteors over the coming week.
Active between the 8th and 17th, the shower is expected to peak overnight on the 13th-14th, bringing more than 100 meteors an hour for an observer under perfect skies. Since high rates persist for more than a day, there should be an excellent show on the previous night, but probably less so on the next one.
The radiant point, from which the meteor paths appear to diverge, lies close to Gemini’s star Castor, which climbs from low in the NE at nightfall to pass high on the meridian at 02:00. Our chart spans some 100° from Leo to Taurus and is centred on Gemini, which stands to the NE of the unmistakable form of Orion. Of course, the meteors appear in every part of the sky – it is just their paths that point back to the radiant.
Travelling at 35km per second, Geminid meteoroids trace long sparkling paths as they disintegrate in the upper atmosphere. However, unlike some meteors, they rarely leave persistent glowing trains in their wake. The meteoroids are thought to derive from the 5km-diameter asteroid Phaethon, which is roasted every 523 days as it sweeps within 21 million kilometres of the Sun at perihelion – closer than any other named asteroid. Its rocks are thought to fracture in the heat, allowing splinters and dust to escape its tiny gravitational pull and spread out around its orbit.
Phaethon passes about 10 million kilometres from the Earth on the 16th in its closest approach since its discovery in 1983, though whether this will result in even more Geminids than usual is questionable. It should be a telescopic object of around the tenth magnitude as it speeds south-westwards from the vicinity of Capella in Auriga on the 11th, through Perseus and Andromeda to the Square of Pegasus.
Also plotted on our chart are Praesepe, the Beehive, in Cancer, and M35, at the feet of Gemini, which are both open star clusters just naked-eye-visible but easy through binoculars. Hydra the Water Snake, the largest constellation, stretches more than 100° around the sky from its head to the S of Cancer to the tip of its tail, which lies S of the conspicuous planet Jupiter in our SE predawn sky. The Moon stands above Jupiter and to the left of Mars on the morning of the 14th. Star-lovers and sky-enthusiasts can enjoy a meteor shower display on December 13 after 10 p.m., and in the early morning hours of December 14, if clouds and light pollution do not play spoilsport. Reach a spot without city lights, maybe the suburbs, and you can enjoy the Geminid meteor shower. Here, Dr. Debiprosad Duari, Director, M. P. Birla Planetarium, Kolkata explains meteors and the Geminid meteor shower.
Monday, 4 January 2016
This is the largest glacier calving event ever captured on film
This is the largest glacier calving event ever captured on film
Posted by Incredible Underwater Discoveries on Monday, January 4, 2016
Friday, 27 November 2015
Eastern Skies
About 5 years ago I started getting into researching
areas of the East Coast that have dark skies such as the western states.
I was told it doesn't exist but I continued my search. I came across a
small section of West Virginia called the Monongahela Nation Forest.
There are only 2 roads that pass between towns that have 1 gas station
and a small convenience store. Located 4 hours from Washington D.C., I
knew I'd be doing a lot of driving. After a few years of scouting the
locations on Google Earth and in person, I started shooting the spring
of 2014. I was also focusing some time down at North Carolina's Outer
Banks. Cape Hatteras is the most outer point of the famous OBX with
very little light pollution, dark skies and amazing historic light
houses. EASTERN SKIES was shot over a 10 month period or 2 full Summers /
Falls. I battled some of the most extreme thunderstorms, insane fog,
dew and anything else mother nature threw at me.
DSLR Bodies
Canon 5d mk3
Canon 6d
Canon 5d mk3
Canon 6d
Lenses
Canon 16-35L 2.8 II
Canon 14mmL 2.8 II
Canon 70-200L 2.8 II
Tamron 15-30 2.8
Canon 16-35L 2.8 II
Canon 14mmL 2.8 II
Canon 70-200L 2.8 II
Tamron 15-30 2.8
Motorized Gear
-Kessler
-Emotimo
-Kessler
-Emotimo
Music
"Dwell"
Tony Anderson
"Dwell"
Tony Anderson
For licensing inquiries, please email mikezorger or visit mikezorger.com
Eastern Skies from Mike Zorger on Vimeo.
NEW YORK CITY - TIMELAPSE
Lumixar is a boutique video production company in San Francisco.
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NEW YORK CITY - TIMELAPSE from LUMIXAR on Vimeo.
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