Invasive species

Invasive species are those that get introduced to a new ecosystem, where they end up replacing or affecting the native fauna or flora. These are mostly introduced by humans. Let's read up on a few of the invasive species.


The wild pigs are native to Eurasia and parts of North Africa. Also called wild boar or feral hogs, the wild pigs arrived in the 1500s in the U.S. and are one of the most invasive species in North America. They were shipped in by Spanish colonisers as a mobile meat source. Over time, they populated the forests of the southeastern U.S., where their genes got mixed with escaped domestic pigs. They are such a threat as they can live anywhere, eat anything, and have a very high reproductive rate. They destroy crops, landscapes and spread diseases.


A small bark insect, the mountain pine beetle depends on a host tree to feed and lay its eggs. They may seem inconspicuous, with just about one-fourth of an inch in length but they are one of the worst invasive species. They have had a massive impact on the pine forests, boring holes in the tree's bark. They lay eggs in these holes under the bark and deposit a fungus that eventually kills the tree. In fact, in 1995, an outbreak of this pest in the western United States and Canada led to the destruction of millions of acres pine forest.


The Burmese python is one of the most concerning invasive species in South Florida where they have established a breeding population. They have even replaced alligators as the apex predator in Florida and have led to the decline of many native species, with the population of small animals dropping at alarming rates. Populations of raccoons, opossums, bobcats, marsh rabbits, cottontail rabbits, and foxes have all been on an alarming decline. These pythons got introduced as a result of the exotic pet trade after they escaped from their owners or got intentionally released into the wild by their owners.


The brown tree snake was introduced to the Pacific island of Guam in the 1950s. And ever since its introduction, it led to the decimation of the native bird and animal populations on the island. It is believed to have been introduced via cargo ships or aircraft. The snakes which easily spread across the island also cause power outages when they climb electrical wires! Among the 11 native bird species in Guam, nine species went extinct after the snake's introduction.


European starlings are an invasive species in the United States. Interestingly enough, its arrival was the result of a plan to introduce all the species referred to in the works of English playwright William Shakespeare. These birds are native to Europe, Asia and northern Africa but easily took to the landscape of the U.S. and spread quickly across the country, affecting the population of native bird species.


One of the worst invasive species in the world, Lantana camara was introduced in India by the British in the 1800s. It came in as an ornamental plant but ended up taking over several ecosystems as an invasive plant. Its ability to spread on the forest floor, climb over trees as a creeper or entangle with other native plants aided it in establishing itself. It continues to spread in India even as methodologies are being adopted to weed it out.

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What is the meaning, origin and usage of word ‘Foundling’?

Meaning: A noun, the term foundling refers to a baby that has been abandoned or deserted by its parents and is found and cared for by others.

Origin: The term has its origins in Middle English fundelyng and is arrived at by combining 'found' (past participle of find') and the suffix-ling' meaning "small or immature." It's been in use since the 14th Century.

Usage: She is a foundling and has grown up in a home for abandoned children. The book narrates the touching story of an elderly woman adopting a foundling and giving her a bright future.

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What is the meaning, origin and usage of word ‘Indomitable’?

Meaning: An adjective, "indomitable" means incapable of being subdued or defeated.

Origin: The word has its origin in late Latin, from the word indomitabilis which means untameable, from in (not) + Latin domitare (to tame). Its fust known usage was in 1634.

Usage: Despite the curveballs life threw at her, June had an indomitable spirit which helped her surmount the difficulties she encountered.

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What is the meaning, origin and usage of word ‘Unprecedented’?

Meaning: The word unprecedented denotes something that is never done or known before.

Origin: The word has been around since the 1620s and is in common use from around 1760. It is arrived at by combining ‘un’ with precedented. Precedented is the past-participle adjective from precedent and conveys the meaning "authorised by precedent, in accordance with established custom."

After steady usage through the 19th Century, the word's usage increased constantly through the 20th Century and its usage is now close to its peak.

Usage: The Australian women won an unprecedented sixth Women's T20 World Cup in 2023.

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What is the meaning, origin and usage of word ‘Fruition’?

It refers to the point at which something is realised or accomplished, often indicating the fulfilment or completion of a goal, plan, or desire.

Origin: The word originated from the Latin word "fruitio," which means "enjoyment" or "use." It entered the English language in the late 15th century.

Usage: After years of hard work and dedication, Sarah's dream of starting her own business finally came to fruition.

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What is the meaning, origin and usage of word ‘Sedentary’?

Meaning: This is an adjective referring to what is characterised by much sitting and little physical exercise.

Origin: The origin of the word lies in the Latin verb sedere, which means 'to sit’. This root word produced two Latin adjectives: sedens, which is quite common in Latin and just means 'sitting', and sedentarius, which is rarer and has the more specific meaning of 'tending to sit around a lot’. These words found their way into English as sedent and sedentary respectively. However, sedent is used rarely while sedentary has come into its own as we find ourselves increasingly in need of a word that describes our tendency to sit down and stare at a screen all day.

Usage: We can ensure ours is not a sedentary job.

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The right space for writers

From cosy nooks tucked away in bustling cities to serene hideaways nestled in nature's embrace, authors have long sought out perfect writing spots to unleash their creativity. In this article, we delve into the cherished writing sanctuaries of renowned authors.

Maya Angelou

Maya Angelou, the renowned poet and author, found solace and inspiration in the privacy of hotel rooms, often choosing them as her dedicated writing spaces. Even when she had a permanent residence, she would frequently rent hotel rooms, maintaining one in her hometown as of 2013. In these rooms, she would create a personalised environment by keeping the sheets unchanged and removing any artwork from the walls. The American memoirist had a specific routine: she would leave her home early in the morning, arriving at the hotel room around 6.30 a.m. While writing, she would often lie across the bed, with her elbow becoming calloused from the constant support. She never allowed the hotel staff to change the bedsheets since she used them solely for writing, not for sleeping. Angelou would continue writing until late morning or early afternoon before returning to her home. This unique practice allowed her to find the focus and inspiration needed to produce her remarkable literary works.

Agatha Christie

Agatha Christie, the youngest of three children, received her education at home from her mother, who consistently encouraged her writing pursuits. Known for her classical detective stories, the English author did not have a dedicated writing room. Instead, she carried notebooks with her and would jot down plots, meticulously labelling each notebook. While there is speculation that Christie conceived many of her masterpieces while sitting in her large Victorian bathtub, eating apples, this detail is not confirmed. According to reports, she claimed that the plots for her books took shape and were refined during everyday activities such as washing dishes, bathing, eating, and walking. These ordinary moments provided fertile ground for her creative thoughts to unfold. Regardless of the precise locations or circumstances, Agatha Christie's remarkable ability to craft intricate and captivating plots remains legendary.

E.B. White

E.B. White is renowned for his beloved book, Charlotte's Web, which captured the hearts of readers with its endearing characters, Wilbur the pig born a 'runt and the spider Charlotte. Interestingly, the American author did not seek out the quietest corner to write. Instead, he often chose to work in his living room amidst the bustling activities of everyday life. He embraced the constant movement around him, and his family members would carry on as if he were not even present. As White believed, "A writer who waits for ideal conditions under which to work will die without putting a word on paper."

Henry David Thoreau

Henry David Thoreau, the renowned American author and philosopher, had a deep connection with nature and sought solitude in his writing endeavours. His most famous work, Walden, was largely inspired by his time spent living in a small cabin near Walden Pond in Concord, Massachusetts. Thoreau's writing spot of choice was within the confines of his humble cabin, from where he could enjoy the picturesque view of the pond and immerse himself in the serene natural surroundings. This setting allowed him to reflect on his observations, thoughts, and experiences, ultimately shaping the introspective and contemplative tone of his writing. He was also among the chief leaders of the Transcendental Movement in English literature (which lasted from about 1830 to 1860) that promoted self-education and the development of the individual. Transcendentalists strongly championed the idea that nature possesses a divine spirit that can help us connect to the rest of the world.

Charles Dickens

Charles Dickens is widely recognised as one of the greatest authors in history. Throughout his illustrious writing career, the English novelist penned a collection of timeless novels that continue to capture readers hearts. Some of his most beloved works include Oliver Twist, A Christmas Carol Nicholas Nickleby, David Copperfield, A Tale of Two Cities, and Great Expectations. These books form an impressive resume of literary gems. To create these literary treasures, Dickens insisted on writing at his familiar desk and chair. He firmly believed that his best work flowed from the comfort of his cherished writing space. In fact, he held such a strong attachment to his desk and chair that he would have them shipped to him when he ventured away from home for extended periods. Today, these iconic items are put on display at the Charles Dickens Museum, located at the authors former home in London.

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What is Vikram Seth famous for?

Vikram Seth is the author of "A Suitable Boy", one of the longest books ever published in English. As the literary world celebrates 30 years of "A Suitable Boy", let's read up on the Indian author who seamlessly shifts between different genres.

Indian author Vikram Seth is noted for his magnum opus "A Suitable Boy", one of the longest books ever published in English literature. And despite it running into more than a thousand pages, the book was widely celebrated and Seth made an indelible mark on the literary world.                 

Early life

Seth was born to Leila Seth (judge) and Prem Nath Seth (business executive), on June 20, 1952, in Kolkata, India. He was raised in London and India. After attending Indian schools, he graduated from Corpus Christi College, Oxford.

In 1978, he received a master’s degree in Economics from Stanford University and later studied classical Chinese poetry and languages at Nanjing University, China. He returned to India to live in New Delhi in 1987.

Writing career

Originally a poet, Seth is known for seamlessly shifting between different genres of writing and coming up with compelling works. Seth's first volume of poetry "Mappings" was published in 1980.

It was after he published the humorous travelogue "From Heaven Lake" (1983) that he gained critical attention. The story centred around his hitchhiking journey from Nanking to New Delhi via Tibet. The first novel to be published was "The Golden Gate". "All You Who Sleep Tonight.", "Beastly Tales from Here and There" and the poetry collections "The Poems, 1981-1994" (1995) and "Summer Requiem" (2015) are some of his other works.

"An Equal Music' (1999), a love story revolving around the world of professional musicians is yet another noted work of his. A lesser-known fact is Seth's musical acumen must have helped him in writing this piece. He was even commissioned to write a libretto (text of an opera) for the English National Opera in 1994. It was published as "Arion and the Dolphin". It is said that his work "Two Lives" is dear to his heart as it is part memoir, part family history. It revolves around the story of Seth's great aunt "Henny", a German Jew, and his Indian great uncle "Shanti".

Through the book he is not only retelling their story but also trying to find answers to the unique alliance between a German Jew (who lost her family in the Holocaust) and his great uncle who served in the Second World War.

Having travelled widely and lived in Britain, California, India and China, Seth drew inspiration from his experiences for his writing. His first novel "The Golden Gate: A Novel in Verse" (1986) revolves around a group of friends living in California. The book won the WH Smith Literary Award and the Commonwealth Writers Prize (Overall Winner, Best Book). He has also authored a travel book "From Heaven Lake: Travels Through Sinkiang and Tibet (1983)", which traces the journeys through Tibet, China and Nepal. It won the Thomas Cook Travel Book Award. "Beastly Tales from Here and There" (1992) is a children's book that has ten stories about animals which are told in verse. He has also translated the works of Chinese, German and Hindi poets.

A Suitable Boy

Seth turned to prose in "A Suitable Boy", exploring the relationships between four Indian families. The book is noted for its gripping narrative style. Despite the fact that "A Suitable Boy" ran to 1,349 pages, it didn't deter readers and sold over one million copies worldwide.

The author took some eight years to write "A Suitable Boy". Set in India around the time the country had gained independence, the book follows a mothers quest to find a suitable boy to marry her daughter Lata Mehra. It was critically acclaimed and was also made into a BBC mini-series by Mira Nair in 2020.

For the past few years, the literary world has been waiting with bated breath for a sequel to this book called "A Suitable Girl". The story is believed to be set in contemporary India, as our former protagonist Lata, now a grandmother, tries matchmaking for her grandson. As the wait for his next book continues, why don't you pick up "A Suitable Boy" and give it a read?

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What are some examples of things written about in science fiction that became real?

Battle tanks, debit/credit cards headphones, bionic parts……… many of the machines and gadgets we use today were predicted by sci-fi authors long ago. Let's look at a few of them that have become a reality

Debit/Credit Cards

Edward Bellamy's 1888 novel ‘Looking Backward’ was a huge success in its day, but it is best remembered for introducing the concept of ‘universal credit’. Citizens of his future utopia carry a card that allows them to spend 'credit’ from a central bank on goods and services without paper money changing hands.

Battle tanks

One of the best-known science fiction writers of the 20th century was H.G. Wells. In his 1903 story ‘The Land Ironclads’, published in the ‘Strand’ magazine, Wells described war machines that were uncannily similar to the modern tank They were approximately 100 feet long and rolled on eight pairs of wheels, each of which had its own independent turning axle. A conning tower in the top let the captain survey the scene. The first battle tanks were deployed on the battlefield a mere 13 years later, during the Battle of the Somme in World War I, and have been an integral part of every country's armed forces ever since.

In ‘When the Sleeper Wakes’ (1899), Wells describes automatic motion-sensing doors which saw reality 60 years later.

Earbud headphones

When Ray Bradbury published his classic ‘Fahrenheit’ 451 in 1953, portable audio players were a reality. However, headphones were massive and ugly-looking. That's why his description of 'seashells’ and thimble radios that brought an electronic ocean of sound, of music and talk is so amazing. He exactly describes the earbud headphone and Bluetooth, which didn't come into popular use till 2000!

Video chat

The first demonstration of video conferencing came at the 1964 New York World's Fair, where AT&T wowed crowds with its 'picturephone’. The technology has come a long way since then, but the first description of video phones came in Hugo Gernsback's serial tale Ralph 124c 41+ in Modern Electrics magazine in 1911. In it, he described a device called the ‘telephot’ that let people see each other while speaking long distance.

Internet glasses

The protagonist in Charles Stross' 2005 book Accelerando, carries his data and his memories in a pair of glasses connected to the Internet. In 2013, Google came out with a wearable computer called Google Glass fitted to spectacles frames. Wearers could access the Internet using voice commands.

All in one novel

Stand on Zanzibar, a 1968 dystopian* novel by John Brunner which won a number of sci-fi book awards, makes several technological and political predictions. These include laser printers, satellite TV, electric cars and on-demand video broadcasts.

Bionic man

Martin Caidin's 1972 book ‘Cyborg’ is the story of astronaut-turned-test pilot Steve Austin who is severely injured in a plane crash. The government engages a doctor who is researching bionics or the replacement of human body parts with mechanical prosthetics that work almost as well as the original. Cochlear implants for the deaf and artificial hearts are successful modern applications of bionics.

*dystopian-pessimistic description of a society that breaks down. Its opposite is 'utopian’.

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Kenya: Where history, nature, and culture meet

Often known as the cradle of humanity, Kenya has fossilised remains of hominids, is home to over 40 ethnic groups, and has the highest concentration of wild animals in the world.

Ranu Joardar

 Kenya, one of the countries in East Africa, has often been described as "the cradle of humanity”. It is an important business, financial, and transportation hub as about 80% of East Africa's trade flows through its Mombasa Port.


Kenya's history dates back to millions of years as some of the earliest fassilised remains of hominids have been discovered here. For instance, findings by anthropologist Richard Leakey in the Koobi Fora area along the shore of Lake Rudolf have included portions of ‘Australopithecus boisei’ and ‘Homo habilis’ (extinct species of human) skeletons.

 An important part of Kenyan history is slavery. During the 1600s and 1700s, most Kenyans were taken as slaves by the Arabs, Europeans, and Americans.

For several centuries, people from across regions have also settled in or travelled to Kenya. The Maasai tribe came to what is now known as central Kenya from north of Lake Rudolf (now called Lake Turkana in the Kenyan Rift Valley) in around mid 18th Century.


Kenya is surrounded by South Sudan, Ethiopia, Somalia, Indian Ocean, Tanzania, Lake Victoria, and Uganda.

The 38th meridian, the longitude that extends from the North Pole to the South Pole, divides Kenya into two halves. Kenya's terrain rises from the low coastal plain on the Indian Ocean towards the mountains and plateaus.

The country's capital, Nairobi, is at an altitude of 5,500 feet. From the west of Nairobi, the terrain descends to the Great Rift Valley, which has jade-green waters of famous Lake Turkana.

Kenya was the first African country to tap geothermal energy (heat energy from the Earth). The Hell's Gate National Park's geysers and hot springs are used to harvest geothermal energy and fuel almost half of Kenya's electricity.

Flora and fauna

Kenya's highlands consist of patches of evergreen forest separated by wide expanses of short grass. The forests have economically valuable trees such as cedar and varieties of podo.

Kenya's ecosystem includes deserts, swamps, and even glaciers on Mount Kenya, Africa's second highest peak. Each region has different plants and animals suited to the area's particular conditions. The semi-desert regions below 3,000 feet have baobab trees.

The Masai Mara, situated in south-west Kenya, is one of Africa's greatest wildlife reserves. It is named after the Maasai tribe, the ancestral inhabitants of the area. It has the highest concentration of wild animals in the world and over 40% of Africa's larger mammals can be found here. During the migration, over 1.5 million wildebeest migrate from southern Serengeti (in Tanzania) to the Masai Mara. They travel 800 km clockwise in a circle through the Serengeti and Masai Mara ecosystems to search for greener mineral-rich pastures and water. The annual migration at the end of the rainy season (usually in May or June) is recognised as one of the "Seven Wonders of the Natural World".

The country's wildlife population is mostly found outside the country's numerous national parks and game reserves. For instance, baboons and zebras are found along the Nairobi-Nakuru highway, near human settlements and urban centres.

The rainforests in highlands have various large mammals such as elephants and rhinoceroses. Besides, bushbuck, colobus monkeys, and galagos are also found in the region. The highlands have predators such as lions, leopards, and wildcats.


The land is home over 40 ethnic groups such as Kikuyu, Luhya, Kalenjin, Maasai, Luo, and Kamba. The country is divided into three language groups- Bantu, Nilo-Saharan, and Afro-Asiatic.

In the 19th Century, several Indians and Pakistanis came to the region, thus influencing the country's language - Swahili. Swahili evolved along the coast from elements of local Bantu languages-Arabic, Persian, Portuguese, Hindi, and English. It is the lingua franca, a language used as a means of communication, between populations speaking vernaculars that are not mutually intelligible. It is also the language of local trade and is used along with English as an official language in the Kenyan legislative body, the National Assembly, and the courts.

Most Kenyans live in the highlands. Most of the population is rural and live in scattered settlements. Before European colonisation, the urban areas constituted only the fishing regions, Arab trading ports, and towns that were visited by dhows (sailing boats) from the Arabian Peninsula and Asia. People began migrating from the rural to the urban areas after the country's independence in 1963.

Music and storytelling are important parts of the Kenyan culture. For centuries, the tribes used songs, stories, and poems to pass on their beliefs, history, and customs. Though school is free of cost, most children have to help their families by working the land, tending cattle, cooking, or fetching water.


The country was a colony of the United Kingdom from 1920 till its independence on December 12, 1963 (known as the Jamhuri Day). The first President Jomo Kenyatta was an icon of the liberation struggle, who led Kenya from 1963 until his death in 1978, when Vice-President Daniel arap Moi took power in a constitutional succession.

According to the first constitution after independence, the Prime Minister was appointed as the head of a cabinet chosen by a bicameral National Assembly. Over the years, several constitutional reforms were made, and in 2010 a new constitution was promulgated. The country is now a republic, with a President, a national assembly, called the Bunge, and a legal system.

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Which day is observed as World Zoonoses Day?

World Zoonoses Day is observed every July 6-a time to examine the invisible dangers emerging from the animal world. In this five-point explainer, let's learn about zoonoses and the risk to public health caused by infections spreading from animals to humans.

World Zoonoses Day

In the 1880s, nine-year-old Joseph Meister was bit by a rabid dog in Alsace, France. It was a time when rabies meant death - a terrible one. The victim would sufferflu-like symptoms, progress to anxiety, confusion, and hydrophobia, the fear of water. Naturally, they would refuse to drink water, and death from dehydration was imminent. In desperation, on the advice of their doctor, Meister's parents approached a local scientist who was working on a rabies vaccine. He was none other than Louis Pasteur, and when young Meister was bought in, the former saw his opportunity to use a human test subject, after seeing positive results on dogs. After consulting fellow scientists Alfred Vulpian and Jacques-Joseph Grancher, on July 6, 1885, Pasteur administered the vaccine. To everyone's surprise, the boy made a complete recovery. It is to commemorate Pasteur’s contribution that July 6 is observed as World Zoonoses Day.

Animals-to-human route

Do you know what's common to Sars CoV-2, Ebola, HIV AIDS, SARS, MERS, Nipah, H1N1 (swine flu), and H5N1 (bird flu)? All of these are zoonotic diseases-meaning they are all animal-borne. Zoonoses have different modes of transmission. In direct zoonosis, the disease is transmitted from animals to humans through air, bites, or saliva. In indirect zoonoses, the transmission occurs via an intermediate species (referred to as a vector), which carries the disease pathogen. These pathogens can be viruses, bacteria, fungi, or parasites. Though the world has seen the emergence of diseases throughout history, in the last 50 years, a host of new infectious diseases has spread rapidly after making the evolutionary jump from animals to humans. According to the World Health Organisation (WHO), 70% of emerging human pathogens come from animals. In the last century, at least 10 infectious diseases jumped from animals to humans.

What's driving the spike?

Globalisation, urbanisation, deforestation, encroachment of wild environments, human-animal conflicts, and wildlife trade have led to the spike in zoonosis outbreaks. Experts have also warned that the risk of global pandemics is growing and that zoonotic diseases will continue to emerge and re-emerge. New infectious diseases are a sign of how the world is changing. The more we change the environment, the more we disrupt ecosystems and provide opportunities for diseases to emerge.

Major factors

  • Deforestation and human-animal conflict:  Clearing of forests may bring wildlife out of the forest to nearby human settlement. Many vines east harmlessly with their host animals in forests because the animals have co-evolved with them. But humans can become unwitting hosts for these pathogens when they venture into or change forest habitat and come in contact with the host animals directly or indirectly. New infections can spread rapidly in big cities as population density is higher and people breathe the same air and touch the same surfaces.
  • Wildlife trade: Wildlife trade increases the chances of human animal contact, putting humans at the risk of contracting diseases. For instance, SARS was linked to wildlife trade and eating of wildlife. People who handled, killed and sold wild animals made up nearly 40% of the first cases. Poorly regulated wet markets (a market selling fresh meat, poultry, and other perishable goods) and illegal wildlife trade offer a unique opportunity for viruses to spill over from wildlife hosts into the human population. Bird Ju-H7N9 and HSN9-too originated in wet markets.
  • Mobility of people: Increased movement of people, faster transport and international travel, and greater interconnectivity among megacities pose greater risks of disease transmission.
  • Climate change: Climate change is altering the way animals live and eat. For instance, unusually heavy rains may create favourable environments for bats hosting the virus to reproduce and multiply. Similarly, food scarcity brought about by drought, may lead to more bushmeat hunting, raising the risk of outbreaks such as Ebola. In the American Southwest, years of drought led to a boom in rodent populations. This led to the deadly hantavirus outbreak in 1993.

Readying for the future

With potential for more zoonotic diseases to emerge in the future, WHO has called for a multisectoral "One Health" approach to address this complex heath threat. In 2019, the Tripartite organisations- the Food and Agriculture Organisation of the United Nations (FAO), WHO, and the World Organisation for Animal Health (WOAH) - developed the Tripartite Zoonoses Guide, which was the summation of a global effort of more than 100 experts worldwide to provide guidance and explain best practices for addressing zoonotic diseases in countries. Operational tools have also been developed for assessment, surveillance, and sharing of information by nations.

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What is Reverse Osmosis?

Osmosis is the movement of a thinner liquid into a thicker liquid through a semipermeable partition or membrane when physical external pressure is applied. The thinner liquid dilutes the thicker solution.

Osmosis is a process that occurs in our bodies all the time. For example, after the food we eat is broken down in the stomach, it passes through the intestines. The intestines contract to force the nutrients, which are thinner, to pass through the walls of the intestines into the blood, which is a thicker solution.

In reverse osmosis, exactly the opposite happens. Water that has a high concentration of impurities is put under pressure and forced through a semipermeable partition leaving all the larger particles behind. This process renders the impure water as well as salty water (here the process is called desalination) potable enough to drink.

This is why RO is used in water purifiers. In a purifier, water passes through several stages-a sediment filter, activated carbon filter and ultraviolet light. RO is the final stage. The larger molecules cannot pass through these various filters and RO removes the harmful particles, metal ions and bacteria in the water that remains. This cleans the water thoroughly and prevents diseases caused by contaminated water.

Reverse osmosis is also used in the food industry to make concentrated juices. The traditional heat treatment reduces the quality of heat-sensitive fruits such as oranges. RO reduces the quantity of water in the juice, so it doesn't need to be thickened by heating. For instance, in the production of maple syrup, RO is used to remove the water from the sap before it is boiled into a syrup. Dairy industries use RO to make concentrated milk and whey protein powders.

Since RO units are also manufactured in compact sizes, they can be installed easily which is why a number of home water filters come equipped with it.

RO removes almost all the minerals in the water, which leaves it tasteless. Some RO systems come with a remineralisation filter that adds minerals to the water and makes it more flavourful!

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Can any stone float on water?

Pumice is a light-coloured volcanic rock. When a volcano erupts, the hot lava comes into contact with the cooler air. The lava cools down and solidifies almost immediately.

Secondly, as the pressure rapidly decreases, gas bubbles are created in the rock before it hardens. As a result, the pumice gets its characteristic hard, vesicular (full of cavities) spongy appearance.

Pumice has an average porosity of 90 per cent and is less dense than water. As long as its bubbles are filled with air, it floats. When water enters the pores, the stone becomes heavy and sinks.

It is not uncommon to find floating masses of pumice near volcanic islands in the ocean. In August 2006, the crew of the Maiken, a yacht sailing in the South Pacific near Tonga, encountered a wide belt of densely packed pumice, just after a submarine volcano Home Reef had erupted. The pumice resembled a blanket of sand on water!

Pumice is used in the manufacture of low-weight concrete blocks and stone-washed jeans. Pumice stones are used in pedicure in beauty salons.

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What is acid rain?

Acid rain or acid precipitation is a term used to define any kind of precipitation that is abnormally acidic and contains high levels of nitric and sulfuric acids

What one needs to note here is that normal rain is slightly acidic having a pH value between 5 and 5.6. (pH is a measure of how acidic or alkaline a solution is. A solution with a pH value less than 7 is considered acidic while a solution with a pH greater than 7 is considered basic or alkaline.) Meanwhile, the pH levels of acid rain are lower than normal precipitation and stand between 4.2 and 4.4. Acid rain can also settle onto Earth in the form of fog, snow and so forth.

The cause of acid rain is attributed to human activities, mostly resulting from the combustion of fossil fuels. In some cases, it can be a result of natural causes such as lightning, volcanoes, decaying plant and animal matter, and so on. When fossil fuels such as coal, oil, and natural gas are burnt gases such as sulfuric dioxide and nitrous oxide get released into the air.

The reaction of these chemical compounds with oxygen and water vapour in the air leads to the formation of nitric acid and sulfuric acid which then mix with water molecules in the air. Sometimes, they can get blown away across several kilometres before they fall to Earth as acid rain.

Dangers of acid rain

Acid rains can wreak havoc on an ecosystem. Apart from affecting the water bodies, it affects the plants and animals in that area.

When it falls into aquatic sources, it can harm fishes, insects and aquatic animals. The low pH level can kill the adult fishes and even the eggs I wouldn't hatch when the pH level dips below 3. The biodiversity gets significantly affected by acid rain. Just like how it affects the aquatic ecosystem, acid rain is harmful to land-based ecosystems.

The chemistry of the soil gets altered drastically, the pH level gets lowered and nutrients of the soil get leached away. This affects the plants which rely on these nutrients.

Further, when acid rain falls on the leaves of the plants, it causes direct damage. It has also been observed that the eggs of the birds (species such as warblers and other songbirds) in the affected areas tend to have thinner shells.

What can be done to prevent acid rain? Well, the ideal way is to limit the quantity of sulfuric dioxide and nitrous oxide that gets released into the atmosphere.

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India’s first graphic novel is back in print!

Between 1991 and 1994, Indian graphic artist Orijit Sen drew inspiration from influential works like Art Spiegelman's ‘Maus’ and Keiji Nakazawa's ‘Barefoot Gen’ to create India's groundbreaking first graphic novel, River of Stories. This timeless work serves as a poignant critique of India's idea of development and political practices. It revolves around the fictional Rewa Andolan, closely mirroring the real-life Narmada Bachao Andolan (NBA), a people's movement fighting against the displacement caused by the construction of the Sardar Sarovar Dam. Illustrated entirely by hand, the graphic novel delves into a decades-long struggle raising pertinent questions about the notion of development. Though the dam was eventually built, the movement's core concerns, such as "development for, whom?" remain deeply relevant today.

 Originally published in 1994 and later going out of print, a new edition of this powerful work was released by Blaft Publications in 2022, featuring a foreword by Indian author Arundhati Roy.

River of Stories

This hand-illustrated novel span 62 pages and intricately weaves together two distinct narratives. One revolves around Vishnu, a spirited journalist from Delhi, who embarks on a journey to the valley, documenting the protests of the Rewa Andolan. The other narrative draws upon the rich mythologies of the Adivasis, painting the enchanting tale of Malgu Gayan, a singer whose melodic tunes bring to life the ancient origins of the river.

The new edition

In this new edition, Orijit Sen acknowledges the significant changes that have occurred since he originally penned the graphic novel. The Narmada Bachao Andolan has progressed, and the landscape has evolved. Sen had contemplated creating an illustrated preface. The purpose was to contextualise the scenario of the early '90s and highlight the changes that have occurred in the Narmada Valley since then.

Additionally, he wanted to shed light on the broader situation of Adivasi and indigenous communities in the present time. However, despite having this idea, Sen had never acted upon it. It was Sen's daughter who ultimately convinced him to reprint the book. "She reminded me to see it for what it is: River of Stories might be the first Indian graphic novel, but more importantly, it is almost a historical document that represents a crucial moment in time in the Narmada Andolan," he says.

Picture Credit : Google