10 Important Questions That Test ‘How Good Are You At Elementary Astronomy’?

10 Important Questions That Test ‘How Good Are You At Elementary Astronomy’?

1. At some time in the night a person saw a half moon setting in the west. What time is likely to be?

(a)Midnight                                                                                   (b)Before sunrise

(c)Approximately 3 am                                                            (d)The time depends on the month

2. When a crescent moon is seen to be setting, will the convex edge or the concave edge be downwards?

(a)Always the concave edge

(b)Always the convex edge

(c)Concave edge if before sunset

(d)Concave edge if after sunset

3.Some planets when seen through a telescope show phases like the moon does. Of the following, which is one of them?

(a)Jupiter

(b)Saturn

(c)Mars

(d)Venus

4.The biggest units that are the first subunits constituting the universe are

(a)Planets

(b)Stars

(c)Galaxies

(d)Objects bigger than galaxies called clusters of galaxies

5.We know that during a total solar eclipse, there is a brief nightfall for about two to three minutes in the region it occurs. The sky becomes star-studded, so much so that birds start returning to their nests! The stars that are seen during this eclipse time

(a)will all again be seen on the night that follows

(b)will be seen again on the night that follows, only if they were to the east of the sun

(c)will be seen again on the night that follows, only if they were to the west of the sun

(d)will not be seen on the night that follows

6.Why do planets closer to the sun lack moons?

(a)They are too small to harbour a satellite

(b)The tidal effect of the sun's gravitational does not allow moons

(c)The giant planets like Jupiter and Saturn have captured all their moons

(d)Comets passing close by have knocked off their moons

7. Suppose today evening, the star Sirius is rising in the east. After 3 months, in the evening,

(a)It will not be seen in the sky

(b)It will be seen in between the zenith and the eastern horizon

(c)It will again be seen rising

(d)It will be seen in between the zenith and the western horizon

8. Suppose it is daytime at a place on the moon. How many heavenly objects are seen in the lunar sky?

(a)Exactly one: the sun

(b)Exactly two: the sun and the Earth

(c)Almost as many as you can see at night from the Earth

(d)One or two depending upon the location

9. In a total solar eclipse and an annular solar eclipse

(a)In the latter the sun is farther from the earth than in the former

(b)In the former the sun is farther from the earth than in the latter

(c)In the latter the moon is farther from the earth than in the former

(d)In the former the moon is farther from the earth than in the latter

10. If conditions are favourable for an annular solar eclipse to occur, in which season of the year in the Northern Hemisphere is it likely to occur?

(a)Winter

(b)Summer

(c)Fall

(d)Spring

For Answers of the above questions, Click Here.

Read More

Know More About Whole Grain And It’s Importance For Good Health.

Know More About Whole Grain And It’s Importance For Good Health.

With the increasing trends of vegetarianism and healthful nutritious diet, whole grain foods are on the rise. Companies are working with dieticians to make wholesome foods offering wider variety, quicker meals and richer taste.

What are unrefined grains?

In traditional Indian diets, grains were consumed either in whole form, or as coarse flours made from stone grinding. Today, however, much of the grain is milled and refined and this process removes most of the bran and the germ, and leaves only endosperm.

Whole grains are not processed or refined but used as whole, retaining the germ, endosperm and the outer shell (bran) intact.

What is the use of germ?

The germ of any grain has high nutrition value (vitamin B, vitamin E, antioxidants and unsaturated fats) while the outer shell is rich in fibre, calcium, magnesium, iron, copper, zinc and vitamin B. The endosperm is the storehouse rich in carbohydrates and protein to provide energy. They are better sources of fibre and other important nutrients, such as selenium, potassium and magnesium.

Whole grains are either single foods, such as brown rice and popcorn, or ingredients in products, such as buckwheat in pancakes or wholewheat in bread. Refined foods include white flour, white rice and white bread. Many breads, cereals, crackers, desserts and pastries are made with refined grains, too.

Nutritionists advise to include whole grains in your diet rather than refined grains to maintain the healthy lifestyle one needs to follow.

Advantages of whole grain diet

A slice of commercially prepared white bread has 66 calories, 1.9 grams protein and 0.6 grams fibre. A slice of wholewheat bread has 69 calories and provides 3.6g protein and 1.9g fibre. Studies show that eating whole grains, instead of refined grains, lowers the risk of many chronic diseases. Epidemiological studies conducted till date have revealed that people who consume three servings of whole grains on a daily basis are at a lower risk of being affected by hormone-related cancers by 10-40 per cent, digestive system cancers by 21-43 per cent and stroke by 37 per cent.

Those who consume whole grain products on a regular basis are less likely to gain weight. Whole grain products have been found to have beneficial effects on those suffering from hypertension. Including whole grain products in the diet can help one prevent osteoporosis and many other bone-related ailments. The consumption of whole grains has been linked to reduced risk of coronary heart disease. Whole grains have a slow digestibility, making them contribute positively to the glucose and insulin responses. This in turn, has been found to lower the risk of diabetes. Every whole grain item in your diet helps. They are full of nutrients; including fibre, B vitamins, and magnesium. The dietary fibre (the indigestible part of the plant that is also found in fruits and vegetables) present in whole grains consists of soluble and insoluble fibre. The insoluble dietary fibre prevents constipation. It also lowers the risk of cardiovascular diseases by reducing total and LDL cholesterol levels. Soluble dietary fibre (found in oats and barley) is associated with lowering cholesterol levels and offers a protection against cardiovascular abnormalities.

Management of Diabetes Mellitus:

Whole grains may play a role both in prevention and management of diabetes mellitus. In diabetics, soluble fibre in whole grains causes a slower rise in glucose levels; what is generally referred to as an improved glucose response. This is also because they are more slowly digested than the cereals and thus permit a slower increase in blood sugar levels.

The best way to consume whole grain products is to flake them, grind or eat them whole, cracked or split.

How To Make Your Meal Palatable

Eating a variety of whole grains not only ensures that you get more health-promoting nutrients but also helps make your meals and snacks more palatable. Enjoy breakfasts that include whole grains cereals, such as bran flakes, shredded wheat or oatmeal. Substitute whole wheat toast or whole grain bagels for plain bagels. Substitute low-fat bran muffins for pastries. Make sandwiches using wholegrain breads or roll. Replace with rice with brown rice. Add whole grains, such as cooked brown rice or whole grain bread crumbs, to ground meat and poultry. Try and incorporate whole grains in your chappaties. Prepare them with whole wheat, bajra, jowar, and ragi for maximum health benefits instead of flours. Whole wheat breads, oats, wheat flakes and cornflakes can be used as healthful breakfast cereals. Breads made of rye are also available. Whole wheat pitas and pizza bases are also available now-a-days.

Read More

How To Overcome Feeling Of Worry

How To Overcome Feeling Of Worry

Here are few practical steps.

Change your self-image. You must begin by asking yourself, “what sort of person I am?” How would you describe yourself? A person who is afraid of life, uneasy in many situations and prone to worry?

The way to overcome fear and worry is to change your response to the situations around you. The secret is in ourselves. It is not what happens to us but the way we react to what happens that counts.

Make a positive approach to life. To change tour self-image you must change your reaction to the experiences of life. Begin by counting your blessings and being thankful for your possessions.

Is your mind able to think and plan? Are you able to see the beauty of the countryside, hear and enjoy melodious music, appreciate tasty and healthy food? These are real blessings.

Every day stop a few minutes to appreciate what you have. Begin the day with a positive affirmation “I am going to live this day enjoying good health and happiness”.

Resolve to face life as it really is. If you have problems face them squarely- don’t run away from them or leave them in the back of your mind.

When some misfortune threatens, consider seriously and deliberately what is the worst that could possibly happen. Then be prepared to face it bravely while hoping for the best. You will find that you worry disappears to a great extent. If you have not shirked in facing the worst possible situation, you will find that your worry dissolves altogether.

Remember you have at your disposal your personal gifts and the strength that comes from the heart of the Universe. Accept the situation in which you find yourself. If there is nothing that can be done to change it, realize that you will have to live with it and accept it. Many people become tense because they struggle against something that cannot be changed. The great secret of happy and peaceful living is in the phrase “one day at a time”. It means: “Live one day at a time”.

Realize how much time you have wasted by worrying about the future and regretting about the past. Today is yours to use it to the full.

When you get up in the morning resolve to think of matters concerned with that one day and leave everything else until the next day comes. Do your best to handle these subjects with faith and perseverance.

Plan your day. It is a good thing to make a plan for the day. Just as you budget your money, you should also budget your time.

Do your best and leave the rest. Resolve to do your best at each task and then leave it. It is good to remember that “Even this will pass away”.

You cannot do anything properly if you worry about something you are going to do next. Give all your attention to the matter on hand.

Relax. This is perhaps the greatest word of all. Take time to relax and live in relaxed way.

Make up your mind that you will never rush up. Get up a little early so that you don’t have a rush out for work. Take things quietly and calmly. Get into the habit of taking ”one minute rest” off and on several times in a day.

Fix some time during the day when, for ten minutes or so, you can sit down and relax yourself completely.

Remember that you need to relax your mind as well as your body. Prepare a quiet room for yourself. Let your mind dwell upon the beautiful pictures around you in the room and the beauty you can see from the windows.

Read More

Know More About The Most Melodious Bird Nightingale

No bird has been written so much by poets as the nightingale. Its song is supposed to be the most beautiful of all and nobody has been quite able to describe it. As a matter of fact, this attempt at describing it goes back to Aristophanes, the ancient Greek writer!

According to the poets, the nightingale sings only at night and at almost any season of the year. But this isn't true. The nightingale is a migratory bird and in England, for example, can only be heard between the middle of April and the middle of June. The nightingale does not visit Ireland, Wales or Scotland. On the continent of Europe it is quite abundant in the South, and even goes as far as Iran, Arabia, Abyssinia, Algeria, and the Gold Coast of Africa.

Only the male nightingale sings. His melody is the song of courtship to his mate, which remains silent in a neighbouring bush or tree. He sings during the day as well as at night, but because of other birds, his song is not noticed so much then.

The male keeps singing until the female has hatched out her brood. Then he remains quiet so as not to attract enemies to the nest. He stays on guard, and his notes are short calls to tell his mate that all is well, or to warn her of some danger.

While the nightingale sings one of the most beautiful songs of all birds, its plumage is very inconspicuous. Male and female are very much alike- a reddish-brown above and dull grayish-white beneath.

The nest the nightingales build is somewhat unusual. It is placed on or near the ground. The outside of the nest consists mostly of dead leaves set up vertically. In the midst of this is a deep cuplike hollow, neatly lined with fibres from roots. It is very loosely constructed and a very slight touch can disturb it. There are from four to six eggs of a deep olive colour.

Read More

Know More About Cement And Concrete

Cement is one of the most important raw materials used in construction work because it is the essential ingredient in concrete. Millions upon millions of tones of concrete are used every year in building roads, bridges, dams, and so on. It is cheap, easy to make, and is waterproof and fireproof. It can also be used under water. When concrete is first mixed, it forms a pasty mass that can be cast into any shape. But it quickly sets rock-hard.

Cement Manufacturing Plant

How concrete is made

Concrete is made by adding water to a mixture of cement, sand, and gravel or stone. The sand is called fine aggregate and the stones are called coarse aggregate. The sand fills in the gaps between the larger stones so that there will no air trapped between them. The presence of air would weaken the concrete. The most common type of cement is Portland cement, which is a fine, grey powder made by roasting a crushed mixture of limestone, clay, and other materials. Large lumps of chalk or limestone rock from a quarry are broken down into smaller lumps by powerful mechanical crushers. Then they are mixed with the other materials and water to form slurry. The slurry enters a ball mill where tumbling steel balls grind it finely. From there it passes into a long, cylindrical kiln that slopes slightly downwards and rotates so that the materials gradually move along it. In this kiln the materials are first dried and then heated while-hot to form a hard, coak-like mass, called clinker. After cooling, this clinker is finely crushed into the familiar fine powdery form of cement. A certain amount of gypsum is added to control the rate at which the cement will eventually set.

Concrete Mixer

Concrete is usually mixed on the site where it is to be used in machines called concrete mixers. They have a rotating drum which mixes the ingredients thoroughly together. The wet concrete may be taken to where it is needed in huge buckets, or skips carried by cranes, or it may be pumped into place through a pipeline. Sometimes concrete is supplied ready-mixed in huge mixer trucks, which pour it directly into place.

Concrete may be cast in its final position in moulds made of wood. Or it may be precast into shape and then taken to the site to be assembled.

Reinforced concrete

Ordinary concrete is strong when it is being squeezed, or under compression. But it is weak when it is being stretched, or under tension. If, say a concrete beam is supported only at its ends, this weakness may cause it to crack and collapse. To prevent this weakness, steel wires or rods are cast into concrete. It is then known as reinforced concrete. The strength can be increased further by stretching the wires or rods either before or after they are forced in the concrete.

In pretensioning, the concrete is cast around rods that are being stretched. When the concrete sets, the rods are released and compress the concrete, making it stronger. In post-tensioning, the concrete beam is cast with holes, pulled out, and then anchored so that the beam is under compression. This again strengthens the beam. 

Read More

Know Full About The Combat Dance Of Rattlesnake

The combat dance of rattlesnake is one of Nature’s great oddities. Actually, it is not a dance but a curious kind of wrestling combat, and it is believed to be rooted in the instinct of all animals to protect their own territory.

The encounter takes place when two angry snakes, one of them an intruder, meet head-on. The combatants pause for a moment, and then, with a sudden convulsive movement, they simultaneously raise the forward parts of their bodies straight up in the air to a height of about two feet and press against each other.

At the same time, they intertwine their tails firmly together to give themselves a purchase for their upright positions. It looks like an embrace, but it is not. It is a fight, each snake trying to push the other to the ground. Weaving back and forth in the air, the embattled reptiles slam and press the free portions of their bodies against each other with great force. The back of the head offers the most vulnerable target. Each snake knows that a push at this point can easily topple his opponent. To add power to this push, the snake fills their lungs deeply with air to make their bodies more rigid on the attack.

The fight continues for some minutes, during which time the snakes are completely oblivious to any danger that threatens nearby. Finally one snake is brought to the ground. The victor holds him there for a moment and then allows the vanquished snake to escape and glide away unharmed.

Only male snakes engage in this combat dance. And they fight only to drive their opponent from the field, very much as medieval knights used to do. They do not fight to kill. If so, they would use their fangs on each other, since most snakes are susceptible to the fatal effects of their own venom.

The combat dance has not been observed very often. The well-known herpetologist, Ross Allen, says that he has witnessed it only three times in more than more than forty years spent studying the habits of reptiles.

Read More

Know More About Turning Natural Resources Into Energy

The Sun and its energy

Most of our energy comes from the Sun. The Sun is a big ball of glowing gases, made up mostly of hydrogen. Inside the Sun, hydrogen atoms join together (through a process called nuclear fusion) and become helium. During the fusion process large amount of energy is released. The energy works its way to the Sun’s surface and then radiates out into space in the form of waves. These waves give us heat and light. The energy from the Sun is stored in our food, which provides fuel to our bodies. It happens thus:

• Plants absorb energy from the Sun (Solar energy) and convert absorbed energy to chemical energy for storage.
• Animals eat plants and gain the stored chemical energy.
• People eat plants and meat.
• Food provides the body with energy to work and play.

The Sun stores its energy in Fossil Fuels

The Sun also provides the energy stored in fossil fuels. Coal, petroleum and natural gas are fossil fuels. They come from the remnants of ancient plants and animals over millions and millions of years. This is how it happened:

• Hundreds of millions of year ago, before people lied on Earth, trees and other plants absorbed energy from the Sun, just as they do today.
• Animals ate plants and smaller animals.
• After the plants and animals died, they slowly became buried deeper and deeper underground.
• After millions of years, they eventually turned into coal and petroleum.

Although the buried prehistoric plants and animals changed from over time, they still contained stored energy. When we burn fossil fuels today, the stored energy from the Sun is released in the form of heat. The heat is used to warm our homes and other buildings and produce electricity for our lights and appliances.

How does energy get to you?

Energy from Fossil Fuels

Most of our energy comes from fossil fuels. Your home may be heated with oil or natural gas. You may have a kitchen stove that uses natural gas. Cars need gasoline to run. The following shows how energy goes from a primary source to a form of energy that we can use:

• The fossil fuel is taken to a furnace, where it is burned. The heat produced by the burning fuel is used to heat water that flows through pipes. When the water boils, it becomes steam.
• The Steam is sent to a turbine. The steam pushes against the blades of the turbine and causes it to spin.
• A shaft attached to the turbine turns a generator and a spinning magnet produces electricity in coils nearby.
• The electricity is sent by wires over long distances to homes and businesses. The electricity can then be used for lighting and for running appliances or machinery.

Energy from water

For centuries, people have been getting energy from rushing water. In a hydroelectric plant, water from rivers or dams is used to drive machinery like a turbine. The turbine is connected to a generator, which produces electricity.

Nuclear Energy: In nuclear reactors, Uranium atoms are split into smaller atoms to produce heat. The heat is hen used to produce electricity, just as the heat from burning coal is used.

Read More

Things To Know For Handing A Sick Child

  

Nursing a sick child often requires more skill and understanding. The mind of a child works differently. He has no experience to guide him. A sick child is naturally afraid, even if you have told him he will be well again in a few days.

Child’s imagination: Every child has a highly active imagination, which becomes even more sensitive when he is sick. You must be careful not to increase his fears. Children have heard adults tell tales about illness and death, including all harrowing details. This sort of exaggeration is harmful to child. Then when he becomes ill, and his imagination is already working overtime, he may be almost scared to death. Therefore, try to keep him calm and quiet. Another instance of the fear in a child is the moment when the doctor prescribes an injection. If so, be sure to set a good example yourself. Don’t cringe when the doctor opens his bag. The child may be watching how you react in this emergency. If you are calm and cheerful, he will try to follow your example.

Fortunately, Nature is kind to young children. Most of their illness last only a few days at most. One minute they seem to be sick and at another they are up and running around as if nothing had happened. Except in certain crippling diseases, they rarely have to stay long in bed.

When your child is sick, be sure to consult the doctor early in the day. Don’t wait till midnight, merely hoping for the best. Remember, the earlier the doctor is consulted, the better for the child and also for yourself. A young child does not have the reserve energies of an adult. He can go downhill very rapidly with certain types of infection. Don’t take a chance, consult the doctor early.

Should you pamper your child? Not necessarily. All children like to be considered as heroes. So don’t pamper your child when he is sick. Sometimes they refuse to take prescribed diet and demand their choice. When this happens, try to explain the child how the planned and prescribed diet helps him become normal soon. Help him to act like a grown-up. At the same time do not make a simple illness seem too important. If your child gets too much attention, he may prefer to remain sick or feign sick.

Don’t allow too many visitors at home when your child is sick. Allow him to see Nature as much as possible. Narrate stories with happy endings. He may want to hear some favourite story over and over again. Either you read for him or narrate. Talk about cheerful things and avoid all morbid discussions. The child recovers fast and brings cheer in you.

Read More

Know More About Wolves And Foxes And Their Species

The dog family includes wolves, foxes and jackals. The familiar domesticated dogs, which have been bred into a huge number of different shapes and sizes, probably originated from the grey or timber wolf. Unlike cats, dogs tend to hunt in groups, called packs. Their long, powerful legs enable them to run well and for long periods.

The common or grey wolf,  the largest of the dogs and found in forest, tundra and mountains, varies in appearance across its range. It is also called the timber wolf, steppe wolf, tundra wolf and plains wolf.

Wolves eat a wide range of food, from deer to small mammals and even berries and other fruits. Even though they are common in some places, wolves are very rarely a danger to people. There are 35 species of dogs and relatives. The thirty five species, including grey wolf, live in North America, Europe and across Asia.

Red wolf is found in south eastern North America and is exceptionally rare now. Coyotes are common in parts of North and Central America. They are rather like smaller versions of wolves and their strange night howls are the ‘call of the wild’. The maned wolf lives in tall grassland in South America. It has long, graceful legs and attractive red-brown hair. Like pet dogs, wolves put their ears back and bare their teeth when they feel in danger.

Four species of Jackals live in Africa, Southeast Europe and South Asia; Dingo is found in Australia. Dhole or Asian wild dog is found in India, China, and Southeast Asia; African wild dog is mainly found in Southern Africa.

21 species of Foxes are found worldwide except Australia. Red or Common Fox is one of the most adaptable and widespread of all mammals, living in remote country and also scavenging in towns and cities.

Read More

Know More Importance Of SoyBean And Its Valuable Protein.

One of the richest sources of protein is the soy bean. This simple food contains a complete protein. It has been cultivated in China and Japan for centuries. Soy beans actually contain twice as much protein, ounce for ounce, as meat and four times as much as eggs. Soy beans also contain a high quality vegetable oil that has no cholesterol in it. Soy oil contains lecithin, which s of value in controlling the level of cholesterol within the body. Soy beans are low in carbohydrates, so that diabetic patients can use them freely. They are highly alkaline, and in addition, contain all the important vitamins.

Sprouted soy beans are used in many parts of Asia. They are an excellent source of vitamin C. They are also rich in vitamins A and B complex. Babies who are allergic to cow’s milk can usually take soy bean milk without any trouble.

In some countries a number of foods are made from the soy bean. These include baked beans, canned or frozen green beans, bean sprouts, soy milk an cheese, vegetable shortening, margarine, and salad oil. They are also used in ice cream and sweetmeats, soy breakfast foods, soy sauce, and soy flour. Different types of soy beans are produced for these purposes.

Modern nutritionists and food chemists are busy in many areas searching for new ways of sing this important protein food. Without doubt soy bean is an excellent answer to the problem of feeding an overpopulated world. It is one of our very best foods, Nature’s gift to man.

Read More

To Know About Pioneers of Atomic Age

Antoine Henri Becquerel (1852-1908) was a French Physicist who discovered radioactivity.

Some substances, when they have been exposed to bright sunlight, glow in the dark for some time afterwards. This effect is called Phosphorescence. Henri Becquerel followed in the footsteps of his father and grandfather who had both been well-known physicists. He was interested in crystals which glow (fluoresce) after absorbing sunlight. When Roentgen discovered X-rays in 1895, Becquerel was fascinated. In the meanwhile a Frenchman named Henri poincare, who later became famous as a brilliant mathematician, suggested that phosphorescent substances might give off X-rays. In 1896, a friend and fellow-countryman of Poincare, Antoine Henri Becquerel, decided to put the matter to the test. He exposed crystals of a Uranium compound to sunlight to make them phosphorescent and placed them on thickly wrapped photographic plates. On developing the plates he found that the plates had been blackened by rays from the uranium compounds. It looked as if Poincare had been correct. A few days later Becquerel happened to be developing some old photographic plates to see if they were still good enough to use. The plates had been kept in a drawer in which there were traces of the uranium compounds. He found to his astonishment that those plates had been blackened by the uranium, even though they had been kept in the dark. The blackening had nothing to do with phosphorescence after all. Becquerel had discovered what came to be called radioactivity. He found that the uranium ore pitchblende was more intensely radioactive that even uranium itself. His enthusiasm influenced Pierre and Marie Curie.

The Curies

Becquerel was friendly with Pierre Curie, a lecturer in Physics at the University of Sorbonne in Paris, and his wife Marie, who was a chemist. He mentioned his discovery regarding Pitchblende to them, and they resolved to try to isolate the unknown, powerfully radioactive element that must be present in the ore.

The Curies obtained loads of Pitchblende ‘waste’ from the Austrian government from which the uranium had already been extracted. They worked in an old wood shed in the Sorbonne purifying and separating the ore. In July 1898 they announced that there were not one, but two unknown radioactive elements in pitchblende. They isolated one, which Marie Curie named polonium, after Poland, where she was born. They did not succeed in isolating the second one, which they called radium, until 1902.

For their pioneering work on radioactivity, Becquerel and the Curies were jointly awarded the 1903 Nobel Physics Prize.

The radium the Curies had prepared so far was in the form of a compound. Therefore, they set about producing pure radium. Pierrie, however, was killed in a street accident in 1906, and Marie continued alone. Breaking with all tradition, the Sorbonne offered Pierre’s position to Madame Curie. In 1910 Marie succeeded at last in preparing a minute amount of pure radium. This brought her a second Nobel Prize in 1911. Soon afterwards she helped to found, and became the first director of the Radium institute of Paris.

Marie Curie died of leukemia, a disease of white blood cells. It has since been shown that radiation can cause leukemia, so it is more than likely that Madame Curie died as a result of excessive exposure to the intense radiation from the elements she had discovered. 

Read More

Know great about Mosquitoes its causes and varieties

Mosquito, a two-winged ‘little fly’ is a menace to humankind. It causes blood loss, transmits diseases like malaria, filaria, dengue, chikungunya, and Japanese encephalitis. There is incredible diversity in the mosquito family. Weighing only about 2.5 milligrams, mosquitoes have survived through the ages. Fossil and zoogeographic evidence suggest that these insects evolved during the dinosaur period of Jurassic Age around 250 million years ago. Though dinosaurs are long gone, these small winged creatures have adapted and evolved to produce extensive taxonomic, genetic and ecological diversity.

Where are they found?

Mosquitoes are found throughout the world except in places that are permanently frozen. They are found amply in the tropics and subtropics. The largest population of individual species occurs in the Arctic Tundra. Out of the 3500 mosquito species, about 350 species have been reported in India.

The diseases they transmit

It is estimated that over 700 million people are affected by the diseases transmitted by mosquitoes. Some of the major diseases are: malaria, filaria, dengue, chikugunya, Japanese Encephalitis (JE), yellow fever, Western Nile Fever (WNF), Western Equine Encephalitis (WEE), Eastern Equine Encephalitis (EEE), Venezuelan Equine Encephalitis (VEE), and California Encephalitis (CE).

Varieties of Mosquitoes Anopheles

Anophelinae comprises 450 species. Sixty-six of these are medically crucial for their plasmodium-carrying capacity. In our country, 58 Anopheline species have been recorded of which 10 are known to be malarial vectors.

How to identify Anopheles

Anopheles can be identified by the three to four black spots on the upper edge of the wing. It has grayish brown body and pale bands on maxillary pulp. Male mosquitoes have antennae that look like brush. In females, antennae do not have such dense hairs. The Primary vector An Culicifacies has widespread distribution and can efficiently transmit both ordinary and cerebral malaria. It breeds proficiently during monsoon and causes incidence of malaria intensify.

The other varieties are: An. Stehensi, an urban vector; An.fluviatilis that inhabits hilly regions; An.minimus found in tea garden belts and foothill regions; An.dirus, mainly confined to the forest and forest fringe areas; An.minimus, dirus and fluviatilis maintain stable malaria in the northeastern states. An.Sundaicus is at present restricted to Andaman Nicober islands, though it was earlier prevalent in Odisha. Besides malaria transmission An.gambiae, An. Funestus etc. carry the filarial parasite in some parts of the world including East Africa, Papua New Guinea. An.barbirostris and An.hycranus can transmit Japanese encephalitis virus also.

Why they feed on: Major Anopheline vectors are anthropophilic and feed on the blood of humans inside the house. The biting hours vary through night (depending on the species) with a flight range of two to three kilometers. Their flight sound is not audible.

Where they breed: Anopheles breed in fresh water bodies like riverside, lakes, cisterns, wells, paddy fields etc. But few species can breed even in foul water, muddy ponds and marshlands.

Read More

How Leech Therapy is quite effective in treating patients

The word ‘unique’ denotes ‘one of its kind’ or something very special. Some animals are quite unique in this sense. For instance, the blue whale is unique for its giant size and so also glow worms “Luciferae” that emit greenish glow at night. Likewise, there are a few more creatures which are unique.

Leech the parasite doctor, is a very special physician. Dr Andreas Michalsen and colleagues from Essen, Germany reported that Leech therapy is quite effective in treating patients with osteoarthritis. Twenty-four patients with this wear and tear of the ageing knee problem were given one-shot leech therapy. They allowed four to six leeches to attach themselves to each knee and drink blood for about an hour. They found leech therapy was far more effective than drug therapy.

Leech therapy which benefits those with other causes of pain, was used by the ancient Egyptians, Greek and Indian medicine men. They used the leech to help maintain the humoral balance in the body. They attached leech to the body for the cure, and detached it by sprinkling some slat water.

How it acts as a physician: The leech which is used in medicine is called Hirudo

 Medicinalis. It has five pair of eyes and two sucker both on its front and back side.     .

The head sucker searches and penetrates while the back sucker holds fast to the host. The

Bite of hirudo is painless because it has an anaesthetic that makes the host feel nothing. This substance is under atudy.

The effect of its saliva:  The leech saliva has many other molecules of great medicinal interest. One of the molecules is a vaso-dilator and a histamine that increases the diameter of blood vessels, helping to promote blood flow. Another is an enzyme called hyaluronidase. It breaks down hyaluronic acid, the bonding material of the connective tissue, thus fostering the flow of blood and fluids from affected areas. Another substance in leech saliva is hirudin. It is the most potent inhibitor of blood clotting known to date. Hirudin in leech helps continued blood flow by breaking off the aggregated fibrin plugs that clot and seal blood leaks. Hirudin also shuts off the mechanisms of Factor VIII mediated blood coagulation. Genetic engineers in England are successful in cloning the gene for hirudin and manufacture it through recombinant DNA technology. We have to be thankful to the leech for the benefits it has opened up for modern medicine. Hirudin made it possible to have its cousins balellin and eglin.

How much blood it drinks: Leech drinks hardly 15ml our of the 3000-5000 ml of the human blood. And having drunk, the parasite doctor moves on to chew the cud for six months.

Read More

Test your knowledge about Cell Biology

1.  Citric acid cycle takes place in the    

a. Mitochondria                  b. Lysosome

c. Endoplasmic reticulum   d. All the above. 

2. Prokaryotic ribosomes are

a. 10 S           b. 20 S         c. 70S         d. 80S

3. The organelle that lacks a double membrane is

a. Mitochondria                  b. Lysosome

c. Ribosome                       d.  Nucleus

4. Cell wall is rigid because of

a. Pectin                      b. Lignin

c. Hemicellulose         d. Cellulose

5. Major function of mitochondria in a cell is

a. Secretion                      b. Osmoregulation

            c. Excreation                    d. Fat synthesis

6. Energy currency of cell is

a. ATP                    b. NAD           c. FAD          d. FMN

7. Autolysis is a function of

a. Peroxisomes                 b.Glyoxisomes

c. Lysosomes                   d. Kinetosomes

8. An octamer of four histones complexed with DNA is called

a. Centrosome                  b. Nucleosomes

c. Mesosomes                  d. Endosomes

9. Most of the hydrolytic enzymes of lysosomes fuction at

a. Acidic pH                          b. Basic pH

c. Neutral pH                        d. Any pH

10. Ribosomes were discovered by

a. Palade              b. de Roberits           c. Golgi            d. Porter

11. Chloroplasts contain

a. 50s ribosomes          b. 80s ribosomes

c. 70s ribosomes          d. No ribosomes

12. Lysosomes are discovered by

a. Robert Hook               b. Purkyne

c. Hertwig                      d. Christian de Duve

13. Which is the smallest cell organelle?

a. Lysosomes                       b. Ribosomes

c. Sphaerosomes                 d. Glyoxisomes

14. The organelle not bound by a membrane is

a. Nucleus                          b. Mitchondria

c. Centriode                       c. Chloroplast

15. Lysosomes are generally found in
1. Animal cells
2. Both animal and plant cells
3. Planet cells
4. Bacterial cells

16. Silicified cell wall is unique to

a. Blue Green Algae           b. Green bacteria

c. Diatoms                          d. Dinoflagellates

17. The term protoplast was coined was coined by
1. Robert Hooke
2. Antony Von Leeuwenhoek
3. Purkinje
4. Hertwig

18. Ribosomes can be seen within

a. Endoplasmic reticulum         b. Lysosomes

c. Golgi complex                      d. Mitochondria

19. Acrosome of human sperm is made up of

a. Endoplasmic reticulum            b. Golgi complex

c. Lysosomes                               d. Centroids

20. Glycolysis pathway was discovered by

a. Calvin                          b. Krebs

c. J.C. Bose                     d. None of the above

21. Both respiration and photosynthesis require

a. Magnesium                      b. Cytochrome

c. Energy                             d. All of above

22. DNA replication takes place in

a. S phase                     b. Go phase

c. G2 phase                  d. M phase

     ANSWERS:

    

     1.a        2.c      3.b      4.b        5.d       6.a       7.c

     8.b        9.a     10.a     11.c      12.d     13.a     14.c

     15.b      16.c   17.c     18.d      19.b     20.b     21.d

     22.a

Read More

How to prolong the life of your cell phone rechargeable battery

I know my this post helps you that how you conserve your battery power if you reach in any remote areas and you have no charger of your phone. It will shows you how to keep your battery well. Ok, so these are the steps for prolong the life of your rechargeable battery.

How to prolong the life of your cell phone rechargeable battery

• If you are in an area with no reception, e.g a basement or remote area, turn the cell phone off since constantly searching for service depletes the battery fairly quickly.
• The vibrate function uses up a lot of battery power. So, switch it off when not needed and use only the ring tone.
• The back light of the phone uses up power- either turn it off or set it reduce the time for which it is on.
• Turn off Bluetooth, WiFi, GPS and infrared capability when not in use- they drain the battery pretty fast.
• High temperature is an enemy of the battery. Keep the battery cool- avoid leaving your phone in a hot car or in direct sunlight.
• Initialize a new battery by charging it fully before its first use to obtain maximum capacity. Nickel-based batteries should be charged for 16 hours initially and run through 2-4 full charge/full discharge cycles. Lithium ion batteries should be charged for about 5-6 hours.
• Charge your battery correctly, in accordance with its type. Most new cell phones have lithium-ion batteries, while older ones generally have nickel-based batteries. A good rule to follow for nickel-battery cell phones is to discharge them completely once every two to three weeks, and then charge them fully. This is not necessary for lithium-ion batteries.
• A battery which is not being used should be stored in a cool place- put it in a ‘zip lock’ bag and store in a refrigerator. Do not store a battery fully charged- charge it about 40% before storage.
• Similar batteries are used in laptops and cameras, so the same rules apply for charging and storage.

Read More

How To Measure Distances In The Universe

The distances between heavenly bodies in space are very, very large. Measuring these distances in kilometers would mean dealing with very large numbers. The Sun, which is the star nearest to us, is 15,00,00,000 km away. The next star nearest to us is Proxima Centauri, which is 4,00,00,00,00,oo,ooo km away. This, you will realize, is very inconvenient to write or to make calculations with.

    Astronomers, therefore, use special units to measure distances in space. Instead of a kilometer, they use a unit called light year. A light year is the distance that light travels in one year.

       Light travels at an incredible speed of about 3,00,000 km/s. If a spaceship could travel at this speed, it would reach the Moon in just over 1 second!

    So, 1 light year = Speed of light in km/s * number of seconds in a year

     = 3,00,000 * 365* 24* 60* 60 km

     = 95,00,00,00,00,00 km (approximately)

                   12

     = 9.5 * 10

In this respect, Proxima Centauri is 4.3 light years away from us. Light from this star takes over four whole years to reach us. This also means that when you look at Proxima Centauri today, you see it as it was 4.3 years ago!

      

   Time taken for light to reach Earth from Sun

= distance of arth from sun

       Speed of light

=15,00,00,000 km  = 500 s = 8.3 min            

   3,00,000 km/s         

So we can say distance of Earth from Sun is 8.3 light minutes.

Read More

Know more about Lobster

One of the most curious creatures to be found in the sea is the lobster. It is a crustacean, which means a hard-shelled animal. It is related to the crawlfish, the shrimp and the prawn. There are three species of lobsters. American lobsters which live all along the Atlantic Coast from Labrador to the North Carolina, are the biggest members of the family. Next in size is the European lobster, which is found on the shores of the Atlantic. The smallest lobster is the African species found off the Cape of Good Hope.

      Lobster is encased in the suit of armour made of hard shell. This is usually dark green in colour but turns red when the lobster is boiled. The shell covering the front of the body is practically solid. The rest of the shell is divided into seven segments, the last of which forms the tail.

     Lobsters have four pairs of walking legs, two pairs of which have small pincers for feet, with claws in the front. They serve as hands rather than as feet. One of them, the club, is very thick and heavy. It is used for crushing tender objects. The other, the fish claw, is more slender, curved and provided with many sharp teeth. It is used to catch prey and defend from enemies.

     Lobsters usually walk about at the bottom of the sea balanced on the tips of their walking legs. When they are alarmed they make huge backward leaps through the water covering as much as 25 feet at a time.

    The female lobster lays from 5000 to 100000 eggs. She carries them about for some ten months, glued to the swimmerets under her tail. As soon as they hatch, the mother lobster fans the babies away to be on their own. The little lobster swims at the surface for six to eight weeks, during which period it can easily become a meal for some other animal. If it lives, it finally sinks down and makes its home on the bottom, in shallow water.

    One wonders how a lobster grows when it has a hard shell around. All through its life, the lobster moults. This means it sheds its armour, whenever it outgrows it. During its first year it moults fourteen to seventeen times, but when it grows older it moults not more than once a year. 

Read More