18 ,19 and 21 Mar 2016


 

India’s Agasthyamala among 20 UNESCO world biosphere reserves:-

India’s “unique” Agasthyamala Biosphere Reserve in the Western Ghats is among 20 new sites added by the United Nations’ top cultural body UNESCO to its World Network of Biosphere Reserves.

The International Coordinating Council added the new sites during a two-day meeting on Saturday in Lima, capital of Peru, bringing the total number of biosphere reserves to 669 sites in 120 countries, including 16 trans-boundary sites.

The newly adopted sites include 18 national sites and one trans-boundary site shared between Spain and Portugal.

“Home to 2,254 species of higher plants”

“Located in the Western Ghats, in the south of India, the Agasthyamala biosphere reserve includes peaks reaching 1,868 metres above sea level. Consisting mostly of tropical forests, the site is home to 2,254 species of higher plants including about 400 that are endemic,” UNESCO said.

“It is also a unique genetic reservoir of cultivated plants especially cardamom, jamune, nutmeg, pepper and plantain. Three wildlife sanctuaries, Shendurney, Peppara, Neyyar and Kalakad Mundanthurai Tiger reserves, are included in the site,” it said.

Spread across T.N., Kerala

The Agasthyamalai Biosphere Reserve (ABR) was established in 2001 and is spread across the two States of Kerala and Tamil Nadu.

Biosphere reserves are places for learning about sustainable development aiming to reconcile the conservation of biodiversity with the sustainable use of natural resources.

New reserves are designated each year by the International Coordinating Council of the UNESCO’s Man and the Biosphere (MAB) Programme, which brings together elected representatives of 34 UNESCO Member States.

Number of tribal settlements

“A number of tribal settlements with a total population of 3,000 are located in the [Agasthyamala] biosphere reserve. They largely rely on biological resources for their sustenance and recent projects have been set up successfully to reduce their dependence on the forests,” UNESCO said.

There are 18 biosphere reserves in India out of which only nine, including the Nilgiris, Nanda Devi, Nokrek, Gulf of Mannar, Sundarban, and Great Nicobar, had been included in the network.

Protecting swathes of natural habitat

Biosphere reserves in India protect larger areas of natural habitat and often include one or more National Parks and/or preserves, along with buffer zones that are open to some economic uses.

Protection is granted not only to the flora and fauna of the protected region, but also to the human communities who inhabit these regions, and their ways of life.


Dept. of Biotechnology launches fund to tackle anti-microbial resistance:-

In a move to encourage biotechnology start-ups as well as tackle the threat faced by India from resistance to antimicrobial drugs, the Department of Biotechnology (DBT) — through the Biotechnology Industry Research Assistance Council (BIRAC) — has invested an initial $1,00,000 to start an India-focussed seed fund to help groups in India compete for the Longitude Prize. This is a £ 10 million prize offered by Nesta, a U.K. charity, to any individual group anywhere in the world that develops an affordable, effective diagnostic test to detect resistance to microbes.

Renu Swarup, Managing Director, BIRAC, said the collaborations were to encourage more biotechnology start-ups out of India. “BIRAC, since its inception, has supported several social entrepreneurs and we are committed to creating an atmosphere where innovation is encouraged and nurtured,” she said. BIRAC is supported by the DBT.

India faces increasing instances of tuberculosis patients being resistant to front line drugs. Experts say this is due to lax monitoring and profligate prescription by medical authorities that allow these drugs to be easily available. Indiscriminate usage means that bugs are, overtime, able to resist these medicines. The World Health Organisation statistics for 2014 give an estimated incidence figure of 2.2 million cases of TB for India out of a global incidence of 9 million, with instances of drug-resistant TB rapidly rising.

Alongside Nesta, BIRAC also inked collaboration with Tekes, the Finnish funding agency, to improve competitiveness of Indian and Finnish industries through promoting collaboration in different phases of the knowledge innovation chain and it is teaming up with Horticulture Innovation Australia (HIA) for a joint funding programme to support innovative technologies for sustainable horticulture at a global level.

Last December, the DBT laid out a strategy whereby biotechnology would be at the foundation of a $100-billion industry by 2025, rising from the current $7-$10 billion.

Four missions

The National Biotechnology Development Strategy, as it is called, expects to launch four missions in healthcare, food and nutrition, clean energy and education; create a technology development and translation network across India with global partnership.


3D printing could help fix damaged cartilage in knees:-

By 3D bio-printing an ink containing human cells, researchers have now found a way to produce cartilage tissue damaged by injuries or age.

Athletes, the elderly and others who suffer from injuries and arthritis can lose cartilage and experience a lot of pain.

The new process, presented at the 251st National Meeting & Exposition of the American Chemical Society (ACS) in San Diego, the U.S., could one day lead to precisely printed implants to heal damaged noses, ears and knees.

“Three-dimensional bio-printing is a disruptive technology and is expected to revolutionise tissue engineering and regenerative medicine,”

To create a new bio-ink, the scientists mixed polysaccharides from brown algae and tiny cellulose fibrils from wood or made by bacteria, as well as human chondrocytes, which are cells that build up cartilage. Using this mixture, the researchers were able to print living cells in a specific architecture, such as an ear shape, that maintained its form even after printing. The printed cells also produced cartilage in a laboratory dish.

Moving the research from a lab dish to a living system, the researchers  printed tissue samples and implanted them in mice. The cells survived and produced cartilage. Then, to boost the number of cells, which is another hurdle in tissue engineering, the researchers mixed the chondrocytes with human mesenchymal stem cells from bone marrow. Preliminary data from in vivo testing over 60 days showed that the combination does indeed encourage chondrocyte and cartilage production.

What is 3D printing?

3D printing or additive manufacturing is a process of making three-dimensional solid objects from a digital file. The creation of a 3D printed object is achieved using additive processes. In an additive process an object is created by laying down successive layers of material until the entire object is created. Each of these layers can be seen as a thinly sliced horizontal cross-section of the eventual object.

How does 3D printing work?

It all starts with making a virtual design of the object you want to create. This virtual design is made in a CAD (Computer Aided Design) file using a 3D modeling program (for the creation of a totally new object) or with the use of a 3D scanner (to copy an existing object). A 3D scanner makes a 3D digital copy of an object.

3d scanners use different technologies to generate a 3d model such as time-of-flight, structured / modulated light, volumetric scanning and many more.

Recently, many IT companies like Microsoft and Google enabled their hardware to perform 3d scanning, a great example is Microsoft’s Kinect. This is a clear sign that future hand-held devices like smartphones will have integrated 3d scanners. Digitizing real objects into 3d models will become as easy as taking a picture.

Processes and technologies

Not all 3D printers use the same technology. There are several ways to print and all those available are additive, differing mainly in the way layers are built to create the final object.
Some methods use melting or softening material to produce the layers. Selective laser sintering (SLS) and fused deposition modeling (FDM) are the most common technologies using this way of printing. Another method of printing is when we talk about curing a photo-reactive resin with a UV laser or another similar power source one layer at a time. The most common technology using this method is called stereolithography (SLA).

To be more precise: since 2010, the American Society for Testing and Materials (ASTM) group “ASTM F42 – Additive Manufacturing”, developed a set of standards that classify the Additive Manufacturing processes into 7 categories  according to Standard Terminology for Additive Manufacturing Technologies. These seven processes are:

  1. Vat Photopolymerisation
  2. Material Jetting
  3. Binder Jetting
  4. Material Extrusion
  5. Powder Bed Fusion
  6. Sheet Lamination
  7. Directed Energy Deposition

3D printing industry:-

The worldwide 3D printing industry is expected to grow from $3.07B in revenue in 2013 to $12.8B by 2018, and exceed $21B in worldwide revenue by 2020. As it evolves, 3D printing technology is destined to transform almost every major industry and change the way we live, work, and play in the future.

Medical industry

The outlook for medical use of 3D printing is evolving at an extremely rapid pace as specialists are beginning to utilize 3D printing in more advanced ways. Patients around the world are experiencing improved quality of care through 3D printed implants and prosthetics never before seen.

Bio-printing

As of the early two-thousands 3D printing technology has been studied by biotech firms and academia for possible use in tissue engineering applications where organs and body parts are built using inkjet techniques. Layers of living cells are deposited onto a gel medium and slowly built up to form three dimensional structures. We refer to this field of research with the term: bio-printing.

Aerospace & aviation industries

The growth in utilisation of 3D printing in the aerospace and aviation industries can, for a large part, be derived from the developments in the metal additive manufacturing sector.
NASA for instance prints combustion chamber liners using selective laser melting and as of march 2015 the FAA cleared GE Aviation’s first 3D printed jet engine part to fly: a laser sintered housing for a compressor inlet temperature sensor.

Automotive industry

Although the automotive industry was among the earliest adopters of 3D printing it has for decades relegated 3d printing technology to low volume prototyping applications.
Nowadays the use of 3D printing in automotive is evolving from relatively simple concept models for fit and finish checks and design verification, to functional parts that are used in test vehicles, engines, and platforms. The expectations are that 3D printing in the automotive industry will generate a combined $1.1 billion dollars by 2019.


All you need to know about OCD

What is OCD-Obsessive Compulsive Disorder:-

It is a neurobiological disorder caused by the deficiency of a neuro-chemical in the brain called serotonin, which triggers obsessions that are characterised by repetitive thoughts which are intrusive in nature. OCD traps a person in a vicious cycle of obsessions, and this leads to anxiety, fear, tension or irritation. Engaging in compulsive behaviour allows the person to lower that anxiety temporarily, but a fresh obsession is triggered soon enough.

Treating OCD

Depending on the severity of the case, the doctor treats the patient through medication or cognitive behavioural therapy (CBT). In some cases, due to their severity, doctors use medicines and CBT to treat the patient. The treatment is often for 16 to 20 sessions, with one session lasting 60 minutes. Early identification and motivation towards treatment is the key to recovery.

So when do you have to seek treatment? When the obsessive behaviour is time-consuming, causing substantial distress and severely affecting work, family and social life, it is time.

Most get the condition before the age of 25

A whopping 65 per cent of people who develop OCD do so before the age of 25. For less than 15 per cent, it happens after 35. OCD is equally prevalent among male and female adults, but when it comes to adolescents the condition is more common among boys.

TYPES OF OCD

* Contamination obsession

A person suffering from this condition has a fear of contamination by dust, dirt and even body fluids. He avoids touching objects, relies excessively on hand sanitizers, and is constantly washing his hands with soap and water. In extreme cases, he may spend hours in the bathroom

* Aggressive obsession

In this condition, the patient is convinced that a close family member or a friend will come to harm. He becomes consumed with checking up on them. In one case, a son would call up his mother 30 times a day just to make sure she is safe.

*Pathological doubts

It’s typified by constant doubts and worries. For instance, the patient may always be checking to ensure that the doors are locked, or that the geyser is switched off. Repeated counting of cash and other items in large numbers is also a trait. The actions cause distress and often extend to a condition termed ‘proxy compulsion’, where the person forces a family member check on the door locks, thus resulting in tension and quarrels.

* Hoarding obsession

When an object, possibly old and unusable, is dear to the patient, he will not discard it at any cost. An attempt by someone else to dispose of the item can cause angry behaviour in the person. There are even cases where people are compelled to save a room full of items and ‘protect’ them from others.

* Sexual obsession

Images of known persons constantly cross the mind of the person, and he often imagines physical intimacy with the individual(s). The patient rarely acts on the thought but constantly asks forgiveness in his mind for thinking so. The situation leads to severe discomfort, especially when encountering the person at a family gathering or workplace.

* Symmetry obsession

The person seeks extreme perfection at home or workplace and gets angry beyond reason when someone disrupts the order and misplaces or takes away a particular item, be it a book, cup, pen or paper clip.

* Religious obsession

It arises when a person carries out severe mental rituals, mainly prayer and obsession, towards god and religious practices.


New shark and ray species found in Indian waters:-

From the Indian waters, a unique and pleasant challenge has suddenly surfaced — 13 new species of sharks and rays.

Recently, the government had imposed a ban on the export of shark fins. Five species of sharks and two manta ray species found in Indian waters have been included in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora for monitoring its international trade. The protected species have to be accurately identified in the field or at the export/trade levels to ensure their effective protection and prevention of illegal trade.


Do You Know

Why there is a fall in boiling points of water and other liquids at hills where there is fall in atmospheric pressure?

Any liquid boils at that temperature at which its vapour pressure equals that of the atmospheric pressure. At the ground level, water boils at 100 degrees C at normal atmospheric pressure. At very high altitudes, the atmosphere thins and the pressure will be less, so that the water boils at a temperature below 100 degrees C. This makes it difficult to cook in open pans in hilly regions, and we have to use a pressure cooker. In the pressure cooker the pressure inside the container will be 2-3 times higher than at ground level. Hence water will boil at around 120 degrees C, and the materials get cooked completely. Thus one can observe a fall in boiling points of water and other liquids at hills due to the fall in the atmospheric pressure.

Why do ceiling fans have three blades?

Though we find 3-blade ceiling fans more often, we come across, quite occasionally, ceiling fans with four blades and very rarely, five-blade fancy fans, also. We would never see a ceiling fan with six or more number of blades and surely never a fan with a single blade. Irrespective of the number of blades that a fan has, the inter-blade radial sectoral angles are always the same. In other words, the radial sectoral angle is 360/n degrees where n is the number of blades. For example, if the number of blades is 3, then the sectoral inter-blade angle is 360/3=120 degrees and when the number is 4 the angle is 90 degrees. This condition of similarity of inter-blade angles, ensures a zero net effective centrifugal force on the blades and thereby, avoids wobbling of the fan during its running.

Now let us know why we find 3-blade ceiling fans most often. We use any ceiling fan as a device to circulate air which in turn hastens evaporation of sweat leaving a sense of comfort to us. The circulation of air is caused when the fan blades chop the air in front of their leading edges and push the air downwards via their lagging edges. This is achieved by the slight bending each blade has along its length such that the leading edge is slightly above the lagging edge and by a gradually varying (usually decreasing) width it features along its stretch from the motor.

The fan can have more air to cut and push, in each of its revolution, if the inter-blade angle is as high as possible, meaning as low a number of blades (n) as possible. The air can be pushed down more briskly by repeated blows during the fan’s each revolution if the fan has more number of blades (n). In other words, in each revolution of the fan, when running, a higher number of blades, reduces the volume of the air to manoeuvre but renders brisk circulation and a lower number of blades increases the volume of air but reduces air speed. In order to achieve optimal results in both (more air and more gush), we strike a balance by not having too low (2) or too many (4 or more) a number of blades on a ceiling fan. For optimal usage and reasonable power management, the balance is struck with a 3-blade system of fans, most often

Why do one’s eyes become red on consuming alcohol?

Since alcohol causes dilation of blood vessels due to release of histamine so increase in blood flow in vessels. The tiny blood vessels in sclera , the outermost layer of our eyes, become dilated causing bloodshot as well as hot eyes. Our cornea is transparent that’s why we can observe the redness of eyes clearly.

After some time it disappears. Some people tend to have red eyes very soon after drinking and for longer duration due to absence of enzyme ALDH2 (aldehyde dehydrogenase) which is responsible for the breaking of alcohol into acetic acid and vinegar in liver.

This is genetic and very common in people of East Asian descent also known as ‘Asian flush’. Persons with this disorder can develop crimson face, headache, nausea, hot eyes etc. even by consuming as little as one drink. Besides, heavy drinking depletes body of nutrients required for the healthy eyes leading to a condition termed as alcoholic optic neuritis.

Why and how do oceans absorb carbondioxide?

Ocean is the largest carbon sink on earth. It occupies nearly 70% of the earth’s surface. As such, the atmosphere comes into contact with the vast extent of ocean’s surface. The atmospheric CO enters the ocean through steady exchange at surface. This is a physico-chemical process. The difference in partial pressure of the CO between seawater and air facilitate gaseous exchange. The diffusion takes place until the partial pressures across the air-water interface are equilibrated. The following two processes ensure the continuous exchange at the air-sea interface, though occasional supersaturation at the surface film is not ruled out.

The seawater contains millions of tiny, microscopic photosynthetic phytoplankton which utilizes CO during photosynthesis. They convert the CO into sugars and other carbon compounds which ultimately enters the food web. The biological pump transfers carbon dioxide from the surface of the ocean to the deep sea.

Unlike other gases, CO reacts with seawater to form dissolved inorganic carbon, ionic and non-ionic species like dissolved free Carbon dioxide (CO), Carbonic Acid (HCO), Bicarbonate (HCO) and Carbonate (CO). The carbonate system is the unique phenomenon of marine ecosystem. The pH of seawater is regulated by the bicarbonate and carbonate concentrations. Marine organisms combine calcium and carbonate ions in the calcification process and manufacture calcareous material. As the organisms die, the skeletal material sinks and buried in sediments.

Can sun rays reflected by a mirror to a solar panel generate electricity?

The sunrays emanating from sun’s outer surface due to nuclear fusion take about 8 minutes to reach earth’s atmospheric region. They consist of ultraviolet, visible and infrared radiations ranging from 100nm (nanometre) to 100,000 nm. The visible rays ranging from 250nm to 800nm (violet to red) reach the earth’s spherical surface effectively. This range contains 45 per cent of the total solar radiation energy reaching the planet’s ground surface. This visible sunlight generates photovoltaic (PV) current on hitting a solar panel.

The reflective mirror changes the direction of the falling sunlight, not its quality when the reflectivity of the mirror is 100 per cent. But this does not happen in reality. The reflectivity of the mirrors ranges from 40 per cent to 95 per cent. With a mirror of good reflectivity (95 per cent) the intensity of the reflected sunlight will not be affected much. The reflected sunlight can generate PV current almost as effectively as the incident rays.

In the countries located far away from equator (Norway, Sweden etc.) the intensity (power) of sun light will be low (100-300w/m). Here larger sized plane mirror reflects the sun light on to the PV panels. An array of mirrors focuses the low intensity sunlight on panels to boost PV current generation. A big concave mirror also enhances the power of solar rays at the focus.

How do different plants synthesize different foods of different tastes although they use the same input materials?

Yes, different plants synthesize different food materials that taste differently. The commonest synthetic process taking place in plants is photosynthesis, wherein green plants produce carbohydrate (starch) using CO, water in presence of sunlight.

Initially glucose is produced and it is converted to starch and stored by the plant. Plants produce not only carbohydrates, but synthesize several other compounds such as proteins, oils, pigments, alkaloids, tannins, flavonoids , gums, resins, phytohormones, salts, phytochemicals etc.

Some of these compounds are used by the plants themselves but some will be stored in different parts of the plant. Proteins, phytochemicals, phytohormones are very essential for many metabolic activities that take place in plants. Plants do absorb phosphorus, nitrogen, several minerals from the soil using which they can synthesize the substances required for their growth, cell membrane synthesis etc.

Plants store the materials synthesized during their metabolic activity in different forms and circulate them to various parts of plant body to carry out other important functions. For example the pigments, essential oils, flavonoids will be circulated to parts like young leaves, fruits, flowers so as to help the plant in pollination, avoiding grazing animals, seed dispersal etc.

We, human beings are dependent on plants directly, indirectly (meat eaters) for our survival. We consume different plant parts such as grains, vegetables, leaves, spices, fruits, roots, stems etc in our daily life. In grains such as rice, wheat, stems like potato, colocasia (taro), sugarcane, roots like beetroot, sweetpotato the food is stored in the form of carbohydrates viz. starch, sugars. If it is stored in the form of starch it is bland in taste. If it is in the form of sugar as in Beets it tastes sweet.

Depending on the nature of foods stored the requirement of plant nutrients also varies. Though all green plants participate in photosynthesis and produce carbohydrates, the taste of the food varies because different plants store food in different forms.

Taste of the food we obtain depends on the chemical composition of the stored food material. The taste of the food also varies depending on plant part, age of the plant part and the geographical location, nutritional status of the plant.

Why do all metals turn red when heated?

Materially, many of the hard metals are considered as ‘blackbodies’. All those materials that are perfect absorbers of all wavelengths of light when they are cool and emitters of all wavelengths of light when they are heated, are known as blackbodies. However, the wavelength (or colour) of the light they emit with greatest efficiency (maximum light throughput) varies with the temperature that they are heated to or maintained at.

Let us know this wavelength as ‘lambda max’. This means that a blackbody body heated to a particular temperature would appear in the colour of the lambda max wavelength because it is at that wavelength that the optical energy is emitted from the body with maximum throughput.

The ‘lambda max’ and the temperature at which the blackbody is heated to are inversely related; the hotter the black body the lower is the lambda max. This is a universal law, known as ‘Wien’s Displacement Law’ and is independent of the chemical composition and physical fabric of the solid body as long as the body behaves as a blackbody when heated.

In other words, the mathematical product of the lambda max and the absolute temperature of the body is a universal constant, known as Wien’s Constant with a value of about 2.9×10 mK when wavelength is taken in metres (m) and the temperature in Kelvin scale (K).

Accordingly, metals, behaving like blackbodies, would appear in red colour (wavelength of about 700 nanometres) when heated to about 3,800 K (or about 3,500 C).

It is on this basis (Wien’s Displacement Law) that metals turn red when heated (to about 3,500 C). It is also the reason why metal objects exposed to blacksmith’s kiln change their appearance from red to yellow via orange because of gradually raising temperature of the kiln.

Finally, it is worthwhile to know that the surface temperatures of the distant stars and heavenly bodies are estimated on the basis of the spectrometric measurement of the lambda max they emit (after accounting for the Doppler Shift). Since Sun appears yellow, its surface temperature is estimated to be about 5,500 C.

How does a flower bloom after plucking it out of the plant?

Flowers are the reproductive organs of a flowering plant. Flowering normally occurs when sufficient vegetative growth ( i.e leaves, roots) has taken place to support and feed the reproductive parts.

Flowering is influenced by photoperiod (the time of exposure to sunlight), temperature and humidity. These factors mainly influence the number of pollinators, their concentration and formation of seeds. They also decide the blooming mechanism.

Blooming is often preceded or accompanied by an increase in the soluble sugars in the petals. The receptors present in the leaves, namely phytochromes, will send the signals to direct more nutrients, carbohydrates and water to the petals.

This results in a surge in the osmotic gradient and the cells present in the petals expand on receiving more water. Cell walls get loosened and expand considerably and blooming takes place.

Flowering hormones (Florigens C and T) will rush to the bud in high proportion just before blooming. The flowering hormones include Gibberellic acid, and in some plants ethylene, IAA and cytokinins.

Inhibitors also play an important role in the blooming mechanism. These inhibitors are again controlled by photoperiod, temperature and humidity. It’s only when the inhibitor concentration falls below a critical level that buds start developing. So, when all the above conditions are satisfied blooming will happen.

Hence, only the buds that have reached appropriate maturity will bloom after we pluck them because by that time the concentration of sugars, water in their cells, florigens must have reached the required level.

Inhibitor concentration too must have fallen below the critical value. The buds too must have enough reserves of nutrients for blooming even after plucking. Exogenous application of Gibberillic acid can induce immediate flowering and blooming irrespective of photoperiod.

What are the criteria for selecting a location as launching site for satellites?

Several factors influence the choice of a launch site. It should be located away from populated areas. Since it involves moving of heavy equipment to the launch site, rail, road and/or shipping accessibility should be taken care of. Coastal areas become the preferred launch sites. Sriharikota fits all these requirements. Some of the other famous launch sites which fulfil these requirements in the world are: Kennedy site in Florida, U. S., Kourou in French Guiana, South America, San Marco in Africa and Alcantara in Brazil, South America.

Earth rotates from west to east. Man made satellites also go round the earth in the same direction (west-east). When satellites are launched towards east the satellite gains incremental velocity of the earth velocity, as it leaves the earth’s atmosphere. (If one were to launch towards west direction the satellite will lose that much velocity when it leaves the earth’s atmosphere. It calls for unnecessarily higher energy to put a satellite in that way).

Communication satellites are put into geostationary orbit above the equator with zero inclination to the equatorial plane. To achieve this the launch site should be ideally located on the equator or close to the equator. Otherwise the satellite orbit would be inclined to the equatorial plane and it has to be manoeuvred for which extra fuel is required. Also the launch site should be free of human population in and around

After a thorough survey along Andhra Pradesh and Tamil Nadu coastal regions, the founding fathers of Indian Space Programme (ISRO) selected Sriharikota (Nellore, A.P). Sriharikota (with a latitude – longitude of 13 degrees 47` N, 80 degrees 15` E) is a spindle-shaped island formed by backwaters of the Bay of Bengal having around 170 sq km area and a long coast line of about 60 km. It is mostly uninhabited.

An ideal launch site must have the following important criteria:

(a) Must be situated on a sea-coast as during the course of flight, the launch vehicle (rocket) sheds out lot of spent hardware which will impact on the earth and the maximum distance of impact (from launch site) could be even 6, 500 kms at times.

(b) It should have moderate weather conditions. As Sriharikota satisfies all the above conditions it is a preferred launch site.

What exactly is allocated in spectrum allocation?

Here the spectrum means a band of frequencies of electromagnetic waves also called as radio waves. Electromagnetic waves range from extremely low frequency to gamma rays. This includes radio waves used for communication and broadcasting purposes including satellite communications, visible region light, infrared and ultraviolet rays, X-rays and gamma rays.

Radio waves are used for communication and broadcasting. For example, FM transmissions use the frequencies from 88MHz to 108 MHz, satellite communications use 4000-6000 MHz and 11000-14000 MHz generally and so on. Mobile service providers also use the radio waves normally in the range of 900-1800 MHz.

Two operators cannot use the same frequency in the same region as there will be interference between each other and both the services will get affected. Same frequencies can be used at two different places separated by sufficient distance so that there will not be any interference. This is called space diversity.

The number of voice channels that can be supported depends on the bandwidth of the frequency spectrum allocated. Higher the bandwidth, more the number of channels that can be accommodated. This radio frequency spectrum is a limited resource and different services are allocated different frequencies.

For example, terrestrial TV transmissions use a particular band of frequencies, satellite operators use a particular band, defense personnel use a particular band, police use a particular band for wireless sets, mobile operators use a particular band so that all can operate without any interference to anybody.

As the spectrum resource is limited, a particular agency coordinates and allots the radio frequencies to different users. So basically the users are allocated a band of radio frequencies for their service and this is called spectrum. This radio frequency band is called spectrum.

The operators use these frequencies to provide service and earn revenue. As revenue earned will be high there will be competition to get frequency band and hence auction is done with some regulations.

For example, private FM operators use the FM band , provide radio service and earn revenue from the advertisements. 150KHz bandwidth is sufficient for one FM station as so many FM stations can exist in the 88-108 MHz band allotted for FM radio service.

Why does milk boil over after heating but water does not?

Water is a simple liquid which does not contain any solids (if it is, in ppm level only) and the boiling temperature is 100°C.

Milk is a compound liquid which contains fat in emulsion form, protein in colloidal state and lactose as true solution and the boiling point of milk is 100.5°C. When milk is heated, the fat which is lighter than water is collected on the surface along with certain protein in the form of a layer called cream.

During heating, the water vapour being lighter than all other ingredients in the milk will rise up. Since the surface of the milk is covered with a thin layer of cream, the water vapour gets trapped below the thin layer and layer prevents the water vapour from escaping.

When milk is heated further, the water vapour expands, pressure builds up and lifts the creamy layer up and thus the milk spills out.

But in case of water, the water vapour escapes very easily on boiling since it does not have any layer on the surface to interrupt till complete evaporation of the liquid.

Why is the hole in the ozone layer found over the Antarctica region?

In the atmosphere, some oxygen (O{-2}) molecules absorbed energy from the Sun’s ultraviolet (UV) rays and split to form single oxygen atoms.

These atoms combined with remaining oxygen (O{-2}) to form ozone (O{-3}) molecules, which are very effective at absorbing UV rays.

Ozone (about 90 per cent of it) exists in the stratosphere, in a layer between 10 and 50 km above the surface of the earth.

In the stratosphere, small amounts of ozone are constantly being made by the action of sunlight on oxygen. Ozone depleting substances are mainly alkyl halides or chlorofluorocarbons (CFC). They are used as propellants in aerosol cans, refrigerants, solvents, and fire extinguishing agents.

As they are very stable compounds, when released into the atmosphere, they are not broken down and eventually reach the stratosphere.In the stratosphere, CFCs and Halogens become irradiated by UV light, and decompose rapidly releasing Chlorine (or Bromine) which are the real ozone-killers.

The chlorine atoms react with ozone, to form oxygen and chlorine monoxide.

Chlorine monoxide then combines with another oxygen atom to form a new oxygen molecule and the chlorine continues to split thousands of more ozone molecules.

The lower stratosphere over the South pole is the coldest spot on Earth. From June to September cold winds blow around the region which prevent warmer air from entering.

Small amount of water vapour in the stratosphere freezes and forms thin clouds of ice crystals as the temperatures in the lower stratosphere drops below 80 degree Celsius.

They are called polar stratospheric clouds. These ice crystals convert safe molecules like CONO{-2} and HCl to more reactive ones like HOCl and Cl{-2}.These two compounds release Cl atoms. At polar stratospheric temperatures, this sequence is extremely fast and it dominates the ozone-destruction process.

Another step, photolysis of chlorine peroxide, requires UV light, which only becomes abundant in the lower stratosphere in the spring.

This mechanism is believed to be responsible for about 70 per cent of the Antarctic ozone loss. The arctic polar vortex is much weaker than the Antarctic, as arctic temperatures are several degrees higher, and polar stratospheric clouds are less common and tend to break up earlier in the spring.

Scientists often refer to the part of the atmosphere where ozone is most depleted as the `ozone hole’ but it is not really a hole — just a vast region of the upper atmosphere where there is less ozone than elsewhere.

How does CFCs damage the ozone layer?

CFCs contain chlorine atoms which react with ozone, O-O-O,  forming a normal oxygen molecule, O-O, and a chlorine containing molecule that is still reactive.  CFC molecules are stable over decades and react with each ozone molecule they contact, catalyzing a process where  two  O-O-O molecules become three O-O molecules.

Why is the ozone hole concentrated over Antarctica?

Ozone is a colourless gas. Chemically, it is very active and reacts readily with a number of substances. These reactions cause rubber to crack, hurt plant life, and damage people’s lung tissues. But ozone also absorbs harmful components of sunlight, “ultraviolet B”, or “UV-B, protecting living things below.

Ozone can be destroyed by a number of free radical catalysts, the most important of which are the hydroxyl radical (OH), nitric oxide radical (NO), chlorine atom (Cl) and bromine atom (Br). Human activity has dramatically increased the levels of chlorine and bromine in the atmosphere.

Each year for the past few decades during the Southern Hemisphere spring, chemical reactions involving chlorine and bromine cause ozone in the southern polar region to be destroyed rapidly and severely. This depleted region is known as the “ozone hole”. British scientists discovered this hole in 1985.

The hole in Antarctica occurs in the spring (September to December). It begins with this overall ozone thinning, but it is assisted by the presence of polar stratospheric clouds (PS clouds). During the extreme cold of winter, with no sun for six months, polar winds create a vortex which traps and chills the air; the temperature is below -80 Celsius. The ice in these PS clouds provides surfaces for the chemical reactions that destroy the ozone. This needs light to kick-start the reactions. By the end of spring warmer December temperatures break up the vortex and destroy the PS clouds. Sunlight starts creating ozone again and the hole begins to repair.

Every March to April during the Northern Hemisphere springtime similar, but less pronounced ozone hole forms above the Arctic. The natural circulation of wind, the polar vortex, is much less developed in the Northern Hemisphere above the Arctic.

What is the difference between GSLV and PSLV?

Both PSLV (Polar Satellite Launch Vehicle) and GSLV (Geosynchronous Satellite Launch Vehicle) are the satellite-launch vehicles (rockets) developed by ISRO. PSLV is designed mainly to deliver the “earth-observation” or “remote-sensing” satellites with lift-off mass of up to about 1750 Kg to Sun-Synchronous circular polar orbits of 600-900 Km altitude.

The remote sensing satellites orbit the earth from pole-to-pole (at about 98 deg orbital-plane inclination). An orbit is called sun-synchronous when the angle between the line joining the centre of the Earth and the satellite and the Sun is constant throughout the orbit.

Due to their sun-synchronism nature, these orbits are also referred to as “Low Earth Orbit (LEO)” which enables the on-board camera to take images of the earth under the same sun-illumination conditions during each of the repeated visits, the satellite makes over the same area on ground thus making the satellite useful for earth resources monitoring.

Apart from launching the remote sensing satellites to Sun-synchronous polar orbits, the PSLV is also used to launch the satellites of lower lift-off mass of up to about 1400 Kg to the elliptical Geosynchronous Transfer Orbit (GTO).

PSLV is a four-staged launch vehicle with first and third stage using solid rocket motors and second and fourth stages using liquid rocket engines. It also uses strap-on motors to augment the thrust provided by the first stage, and depending on the number of these strap-on boosters, the PSLV is classified into its various versions like core-alone version (PSLV-CA), PSLV-G or PSLV-XL variants.

The GSLV is designed mainly to deliver the communication-satellites to the highly elliptical (typically 250 x 36000 Km) Geosynchronous Transfer Orbit (GTO). The satellite in GTO is further raised to its final destination, viz., Geo-synchronous Earth orbit (GEO) of about 36000 Km altitude (and zero deg inclination on equatorial plane) by firing its in-built on-board engines.

Due to their geo-synchronous nature, the satellites in these orbits appear to remain permanently fixed in the same position in the sky, as viewed from a particular location on Earth, thus avoiding the need of a tracking ground antenna and hence are useful for the communication applications.

Two versions of the GSLV are being developed by ISRO. The first version, GSLV Mk-II, has the capability to launch satellites of lift-off mass of up to 2,500 kg to the GTO and satellites of up to 5,000 kg lift-off mass to the LEO. GSLV MK-II is a three-staged vehicle with first stage using solid rocket motor, second stage using Liquid fuel and the third stage, called Cryogenic Upper Stage, using cryogenic engine

Different flowers have different smells? Why?

Each flower or the flower family has an aroma (smell). Chemical substances in the plant species contribute to the smell of the flowers, leaves, roots or even fruits. These chemical substances are mostly low molecular weight compounds and volatile in nature so that they could easily spread, and be perceived.

Terpenes and esters are some of the commonly known chemicals that constitute the floral fragrance. However, the foul smelling flowers may have different chemicals including sulphides, amines, phenols, etc. Several compounds may occur in the same plant species and the flower smell between the plant species might vary depending on the chemical constituents and their concentration.

In pollination, the pollen grains (male part) should be transferred to the stigma (female part) of the same flower or different flowers of the same plant species. The organisms that usually get involved in pollination are known as pollinators and they could be insects, birds, etc. These pollinators are usually attracted by the smell and colour of a flower. If all the flowers produce a similar aroma, and if all the pollinators prefer all kinds of smells, there is no reproductive advantage for those flowering plants.

On the other hand, when a flower can differentiate itself from other species by its unique smell and colour, it increases its likelihood to attract more specialized pollinators that could maximize its reproductive success through enhanced pollination. It has evolved in nature through a process called ‘co-evolution’ in which a flower species and its pollinator species adapt to each other’s changes over a long period of time.

Some flowers produce a foul smell like rotting meat, because they are usually pollinated by flies and beetles. Thus, the flower smell is mainly determined by its chemical constituents, and the smell has mainly evolved to attract its preferred pollinators.

What is dark energy?

Dark energy  which is said to exist but scientists know very little details of it. About 14 to 15 billion years ago, when the Big Bang happened, the universe came into existence. The matter formed from huge energy started expanding due to outward force of the Big bang. From the theory of gravity postulated by Einstein, the particles having mass should attract each other and the expansion of the Universe should stop at one point of time.

However from the observations made by the astronomers, it appeared that the rate of expansion has increased after about 7 billion years. This shows that some other force is acting against the gravity which is forcing the expansion of universe instead of contraction. Scientists gave name to this unknown force as the ‘dark energy’.

It is interesting to know that what we see as the matter in the universe in the form of stars, planets, clouds of dust, only forms about 5 per cent of the universe’ mass, rest being dark energy (about 68 per cent) and dark matter (about. 27 per cent).

Drinking soda helps us during indigestion. How?

Soda water or carbonated water is water in to which low levels of pressurized carbon dioxide has been dissolved, creating carbonic acid. The intake of soda water helps those with impaired digestion. Soda water causes bloating, which stretches the stomach. Mechanoreceptors in the stomach detect the stretching resulting in parasympathetic innervations to gastrointestinal (GI) smooth muscles. This results in an increase in GI motility.

Researchers have found that people who drank at least 1.5 L of carbonated water every day for 15- 30 days had a big amelioration in their indigestion and constipation compared to people who drank regular tap water. All carbon dioxide in soda water does not reach the stomach. Much is lost in the fizz when the bottle is opened, and some combines with swallowed air to cause belching and small amount is rapidly absorbed through the wall of the GI system.

Since soda water is a liquid, it easily passes down the oesophagus and the lower oesophageal sphincter relaxes and opens to allow its entrance into the stomach. The upper part of stomach relaxes to store the swallowed soda water. The digestive glands in the stomach lining produce hydrochloric acid, containing pepsin. Stomach mixes the digestive juices with soda water. Upon reaching the small intestine, soda water mixes with secretions produced by the pancreas and liver.

When the stomach is empty, soda water passes rapidly in to the duodenum where carbon dioxide is transformed into bicarbonate. The carbon dioxide dissolved is rapidly released in gaseous form as the fluid is warmed. The free carbon dioxide may be belched if the expanding gas increases the pressure and stimulates the gastric fundus, triggering the belching mechanism. Distention of gastric fundus can increase transient lower oesophageal sphincter relaxation. If the soda water is taken while or after eating it tends to localize in the upper part of stomach and will produce feeling of fullness. Hence, carbonated water seems to influence stomach function by both mechanical and chemical effects.

Why do we laugh when we are tickled?

Touch is an extremely powerful thing. Humans clearly respond to touch, both physically and emotionally. Some areas on our bodies are more sensitive than others, however. Laughing when tickled in our sensitive spots (under the arms, near the throat and under our feet) could be a defensive mechanism.

Beneath your skin lie millions of tiny nerve endings that alert the brain to all manner of touch. When these nerve endings are lightly stimulated — for example, by another person’s fingers or by a feather — they send a message through your nervous system to your brain, which analyzes the message. Using functional magnetic resonance imaging machines (fMRI), researchers have determined that the effect of a light touch that results in a tickling sensation is the result of the analysis of two regions of the brain.

The somatosensory cortex is responsible for analysing touch; for example, the pressure associated with it. The signal sent from the skin’s sensory receptors also passes through the anterior cingulated cortex, which governs pleasant feelings. Together, these two create the tickle sensation. Therefore, when we are tickled the somatosensory cortex picks up the signals to do with pressure, but the anterior cingulated cortex also analyses the signals which leads to pleasurable feelings.

We laugh when we’re tickled because both tickling and laughing activate the Rolandic operculum — a part of the brain that controls facial movement, vocal, and emotional reactions. Furthermore, the laughter from being tickled is part of a defence mechanism to signal submissiveness and the researchers believe that our responses to tickling date back to man’s earliest evolution and developing self-awareness.

The atmosphere contains several gases. A person inhales that combination but how is the oxygen differentiated from that in our respiratory system?

We inhale oxygen, carbon dioxide and nitrogen and also exhale the same gases, though in different proportions to inhalation; that is, oxygen is exchanged for carbon dioxide during breathing.

When inhaling, we take in approximately 21 per cent oxygen, 0.04 per cent carbon dioxide and 79 per cent nitrogen. On exhalation, we give off approximately 16 per cent oxygen, 4 per cent carbon dioxide and 79 per cent nitrogen; only the amount of nitrogen remains constant in the exchange. Exhaled air also contains water vapour. The inhaled air reaches lungs and enters alveoli where oxygen diffuses out from alveoli into blood, which enters into lungs via pulmonary capillaries, and carbon dioxide diffuses into alveoli from blood.

This diffusion happens because of partial pressure difference between oxygen and carbon dioxide in blood and alveoli.

In alveoli, partial pressure of oxygen is relatively higher than that of carbon dioxide whereas, in the blood which enters back in to the lungs, partial pressure of carbon dioxide is higher than that of oxygen.

Carbon dioxide entered into the alveoli by diffusion is exhaled by lungs while we breathe out.

For our body cells to perform various functions, they need energy, and this energy is generated by producing ATP molecules via burning fuel molecules such as carbohydrates using oxygen.

The byproduct of this reaction is carbon dioxide. So in the body cells, partial pressure of carbon dioxide is higher than oxygen. When oxygen rich blood reaches body cells by systemic circulation, because of partial pressure gradient, oxygen will diffuse into the body cells and carbon dioxide which is at higher pressure will diffuse into blood.

The carbon dioxide rich blood returns to the heart (right atrium) and then pumped into lungs. In the lungs, carbon dioxide is exhaled. This process is a cycle and oxygen is taken up and carbon dioxide is released out continuously in our body.

It is general concept that carbon dioxide is bad for the body. It is not so. Carbon dioxide plays one of the most significant roles in body health and well-being. Carbon dioxide regulates the distribution of oxygen in the body. It is also the body’s relaxer. CO is the body’s way of dilating the arteries, especially those in the brain, the heart and the periphery (hands and feet).


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By | 2017-02-13T21:36:57+00:00 March 22nd, 2016|editorials, Science|0 Comments