Category Science

Does the vampire bat feed on blood?

          Stories about vampires have been heard and talked about for centuries. It was said that vampires were the souls of the dead who stalked the country looking for victims to suck blood. These stories existed in Europe long before the blood-sucking South American vampire bat was known to people. In the 1700, explorers to South and Central America related stories about bats which sucked blood. These stories were exaggerated, and it was then that all vampires came to be thought of as bats. 

          Bats are the only mammals that can fly. They are small animals, not more than six to nine centimetres long. The vampire bat of tropical America lives on the blood of other animals and spends about half an hour each night feeding. Vampire bats do not really suck the blood through the puncture wounds made by their fangs; instead they lap it up from the small incision (cut) made by their razor-like front teeth. Their saliva contains an anti-clotting agent and the blood simply comes out while the victim continues to sleep. Although the amount of blood lost by the victim is usually small, there is a risk that this bat can transmit diseases such as rabies. A vampire needs about 30 gm of blood each night and it may take it from one or more animals. Vampires may also suck the blood of a sleeping man, horse, cow, dog or goat.

          Because bats like to rest in dark caves and come out only at night, they are greatly feared by animals. 

Why is a dog’s sense of smell better than that of ours?

          Dog has been a faithful friend of man for thousands of years. Most dogs are kept as pets to do useful work like herding sheep or guarding buildings. Today, there are more than 100 breeds of dog of many colours, shapes and sizes.

          Dogs see a world that is blurred and has no colour. They are short sighted and see only shades of grey. But a dog’s sense of smell is thousand times better than that of ours. If it passes through one place, it can identify the same place again due to its acute smelling power. Therefore trained dogs are used in the modern security system. They can sniff illegal drugs and culprits. Customs officers use specially trained dogs for sniffing out illegal drugs. It is not necessary to open cases or crates – one sniff is enough for a dog, even if the drugs are packed in tins. 

          In our nasal cavity there is a yellowish area of about 250 sq. mm. This contains millions of hair-like cells which are sensitive to smell. These are called chemoreceptors. They are always wet because of the mucus present there. Chemoreceptors are connected to the olfactory bulb in the brain. When we smell something its particles along with the air reach the chemoreceptors. There they produce electrical impulses in the nerves. These electrical impulses reach the olfactory bulb and we identify the smell.

          The smelling power, in fact, mainly depends upon the size of the olfactory bulb. Bigger the olfactory bulb better is the smelling power. Studies have revealed that a dog’s olfactory bulb is bigger than that of a man that is why the dogs have a greater power of smell. Another reason for this characteristic is that the dog’s nasal cavity is wetter as compared to that of human beings. This wetness further helps in identifying the smells.

          Dogs make use of the strong sense of smell in feeding, hunting and identifying enemies. 

Why do rabbits have large ears?

          Rabbit is a small furry mammal with a short tail and large pointed ears. Rabbits live in burrows in the ground. Each burrow is the home of a single family. The first fossils which can be attributed to this family came from North America. But now they are found in most parts of the world. As compared to the rest of its body the rabbit has large-sized ears.

          Rabbit is a weak and timid animal and is usually surrounded by many enemies. Therefore nature has provided it with large ears to enable it to hear even the faintest of sounds. The large area of the ear catches most of the sound waves produced in the air and passes them into the inner ear. This enables the rabbit to detect its enemies in time and to run to safety areas.

         You must have noticed that a rabbit washes its ears by repeatedly licking its forepaws and rubbing them over the surface of its ears. It does this just not to keep its ears clean, but also to take into its mouth the natural oil which covers the ear surface. This oil is important in forming Vitamin D which in turn is necessary for the growth of the healthy bones. If the rabbit is prevented from doing this, it will develop rickets.

          Wild rabbits spend most of the day underground and usually come out for food only between dusk and dawn. They also have a keen sense of smell. They have long, hind legs which give them a good speed. A rabbit can run at a speed of 65 km per hour. Rabbits feed mainly on grass but eat other vegetation also. Their fertility rate is very high. Only their extraordinary fertility has enabled them to survive inspite of their many enemies. On an average a doe (female rabbit) produces 10 to 12 young ones every year. The natural enemies of rabbits are cats, dogs, foxes, minks, weasels and wolves. Man is the biggest enemy of rabbits because he hunts them for their skin, fur and meat.

 

When were the museums started?

          A museum is an institution that collects, studies, exhibits and conserves objects for cultural and educational purposes. They are of several kinds. There are museums devoted to art, science, history, industry and technology.

          The word ‘museum’ comes from the Greek word Mouseion which means ‘temple of the Muses’. The Muses were the goddesses of the arts. One of the first institutions, called Mouseion was founded in Alexandria, Egypt in the 3rd century B.C. Its aim was to collect information that might be of some interest to the scholars. The scholars used to live and carry out their research there. The museum displayed a collection of art pieces and antiquities like statues, astronomical and surgical instruments, elephant tusks and hides of rare animals.

          Later kings and nobles started having their own museums by collecting art objects and antiques from different parts of the world. However, these were private museums, meant only for their families and friends.

          After the French Revolution the doors of the French museums were opened to the general public. In 1793, during the revolution, the Republican Government established a national museum in Lauvre, Paris. For the first time in the 19th century buildings were specially designed for this purpose. One of the first buildings in Europe was the Atles Museum in Berlin, Germany. It was constructed in 1830.

          Today, we have museums in almost all the big cities of the world. They are visited by thousands of people everyday. The oldest museum in the world is the Ashmolean Museum in Oxford which was built in 1679. The largest museum in the world is the American Museum of Natural History in New York. It was founded in 1874. The largest and the most visited museum in the United Kingdom is the British Museum which was opened for public in 1759. Bombay, Madras, Delhi and other big cities in India have museums devoted to different subjects. 

Vinod Johri

Vinod Johri

Vinod Johri (10 June 1935) was an Indian astrophysicist. He was an eminent cosmologist, a retired professor of astrophysics at Indian Institute of Technology, Madras and an emeritus professor at Lucknow University since 1995. Johri had over 75 research publications and articles published in pioneering journals. His major contributions in cosmological research included ‘power law inflation, genesis of quintessence fields of dark energy and phantom cosmologies’. He was the co-author of the first model of power law inflation in Brans–Dicke theory along with C. Mathiazhagan. He was honored by Uttar Pradesh Government by Research Award of the Council of Science & Technology (CSIR).

Institution 

  • Indian Institute of Technology
  • Lucknow University
  • Gorakhpur University
  • Allahabad University

Fields

  • Astrophysics
  •  Physics
  •  Cosmology

Johri spent over 45 years researching in cosmology, acting as a research guide and principal investigator of various research projects of Council of Scientific and Industrial Research, Department of Science & Technology and University Grants Commission of India. Johri was a Commonwealth Fellow, a senior visitor at Cambridge University (UK) and a Fellow of Royal Astronomical Society of London. He worked as consultant for UNESCO at United Nations Development Program[6] in Iran and as a DAAD Fellow at University of Mainz (Germany), as a visiting scientist at Hansen Lab (Gravity Probe B Group) Stanford University (USA) and as an International Scholar at Fine Theoretical Physics Institute at University of Minnesota at Minneapolis (USA). He died in Dallas, USA at the age of 78 due to complications arising from Kidney failure.

TO READ MORE ABOUT VINOD JOHRI CLICK VINOD JOHRI 

Who developed the shorthand?

          Shorthand is a system of writing fast using characters, abbreviations or symbols for letters, words or phrases. Other names for shorthand are stenography (little or narrow writing), tachygraphy (swift writing) and brachygraphy (short writing). Because of its obvious usefulness, today it is widely used in business, industry and other professions of the world.

          Most historians trace back the origin of shorthand to the Greek historian Xenophon who used an ancient Greek system to write the memoirs of Socrates. Marcus Tullius Tiro of Rome invented the Latin shorthand far back in 63 B.C. He also compiled a dictionary of shorthand. 

          However, the systematic development of shorthand took place in the 17th century. John Willis is considered the father of modern shorthand. Later the industrial developments brought in a demand for stenographers in the business. During the 18th century several shorthand systems were developed but the one developed by the English stenographer Samuel Taylor in 1786 was adapted in French, Spanish, Portuguese, Italian, Swedish, German, Dutch, Hungarian and other languages. Sir Isaac Pitman developed the modern system based on Taylor’s system in 1837. It consisted of 25 single consonants, 24 double consonants and 16 vowel sounds.

          Irish born John Robert Gregg developed another system in 1888 which was based on circles, hooks and loops. In 1893 this system was introduced in U.S.A. In the present century rapid strides have been made in this field.

           Nowadays many machines are also available which can record fast speeches. Stenotype machine was invented by Ward Stone Ireland, a U.S. stenographer and court reporter, around 1906. This machine is used for recording speeches. It is especially employed for conference and court reporting.