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Calcium-41 for Radiometric Dating

Context

Recent study shows that Calcium-41 can be used the same way as Carbon-14 in carbon dating, but with several advantages.

What is radio carbon dating?

• Carbon-14 - Radiocarbon (Carbon 14) is an isotope of the element carbon that is unstable and weakly radioactive [The stable isotopes are carbon 12 and carbon 13]
• It has a half-life of 5,700 years, so the technique can’t determine the age of objects older than around 50,000 years.
• Radiocarbon dating – It is a method that provides objective age estimates for carbon-based materials that originated from living organisms.
• Plants and animals assimilate Carbon 14 from carbon dioxide throughout their lifetimes.
• When they die, they stop exchanging carbon with the biosphere and their carbon 14 content then starts to decrease at a rate determined by the law of radioactive decay.
• An age could be estimated by measuring the amount of carbon-14 present in the sample.
• There are 3 principal techniques used to measure carbon 14 content of any given sample.
  • Gas proportional counting
  • Liquid scintillation counting
  • Accelerator mass spectrometry (Advanced method)
• The method was developed 1940s by Willard Libby, who received the Nobel Prize in Chemistry to this work in 1960.
• The issue with carbon dating was to detect carbon-14 atoms, which occur once in around 10¹² carbon atoms.

What is Calcium-41?

• Calcium-41 is a rare long-lived radio-isotope of Calcium that has a half-life of 99,400 years.
• Calcium-41 is called a cosmogenic nuclide, because it is produced when cosmic rays from space smash into calcium atoms in the soil in a fission reaction, called spallation.
• It is found in the earth’s crust, opening the door to dating fossilized bones and rock.
• The issue is Calcium-41 is rarer, occurring once in around 10¹⁵ Calcium atoms.

How can the issue of detecting C-14 and CA-41 be resolved?

• Atom Trap Trace Analysis (ATTA) - Researchers at the University of Science and Technology of China pitched a technique called atom-trap trace analysis (ATTA) to spot these atoms.
• ATTA is both extremely sensitive and selective, and is based on the laser manipulation and detection of neutral atoms.
• Procedure - A sample is vaporised in an oven.
• The atoms in the vapour are laser-cooled and loaded into a cage made of light and magnetic fields.
• In ATTA, a laser’s frequency is tuned such that it imparts the same energy as required for an electron transition in Calcium-41.
• The electrons absorb and release this energy, revealing the presence of their atoms.
• Significance - It can spot one calcium-41 atom in every 10 ¹⁶ calcium atoms with 12% precision in seawater.
• ATTA also avoids potassium-41 atoms, which are similar to calcium-41 atoms but lack the same electron transition.
• It can also be modified to study isotopes of some noble gases that have defied techniques developed for carbon-14, such as argon-39, krypton-81, and krypton-85.

What are the applications of ATTA and Calcium-41?

• Opens the possibility of extension to other metal isotopes
• To study how long rocks has been covered by ice
• Open avenues for exploring Earth-science applications

The Genetic Legacy of Neanderthals in the Human Nose

Context

Recent research conducted by a team of scientists from the University College London and Fudan University, in collaboration with researchers worldwide, has shed light on the genetic factors influencing the human nose.

• The study identified genetic loci associated with the nose, including one locus influenced by Neanderthal ancestry.

What are the Key Highlights of the Reasearch?

• The Genetic Study:
  • The study analyzed 2D images and measured distances between facial landmarks in over 6,000 Latin American individuals.
  • The research identified 42 new genetic loci associated with the nose, with 26 of them being replicated in diverse populations including Asians, Europeans, and Africans.
    • A ‘locus’, plural ‘loci’, is the position of a particular gene on the human chromosome.
  • One specific locus, 1q32.3, previously linked to Neanderthal genetic contributions, was found to influence midface height.
    • The 1q32.3 locus contains the gene ATF3 (activating transcription factor 3), which is regulated by the forkhead box L2 (FOXL2) gene involved in skull and facial development.
• The Legacy of Neanderthals:
  • Genetic evidence suggests that Neanderthals and early humans interbred, leading to the introgression of Neanderthal genomic sequences into the human population.
  • The influential work of evolutionary geneticist Svante Pääbo, who won the Nobel Prize for Physiology and Medicine in 2022, has provided key insights into the interbreeding events between archaic hominids, such as Neanderthals and Denisovans, and modern humans.
    • This interbreeding has left lasting genetic imprints on our species, affecting various traits and disease susceptibilities.
    • Non-African populations today carry about 1-2% of Neanderthal DNA, highlighting the genetic legacy of this interbreeding event.
  • Apart from nose shape, Neanderthal genetic contributions have been implicated in the way humans respond to pathogens and their susceptibility to certain skin and blood conditions, cancers, and even depression.
  • The study highlights the growing body of evidence indicating the profound impact of Neanderthal and Denisovan genomes on modern human biology and health.
• The Future of Genomic Research:
  • The investigation of interbreeding events and their consequences represents an exciting frontier in genomic research.
  • As more studies contribute to our understanding of the interplay between archaic and modern human genomes, we will gain a more comprehensive picture of our genetic heritage.
  • This knowledge has the potential to revolutionize the study of diseases and enhance our appreciation for the intricate tapestry of human genetic diversity.

Solar Ultraviolet Imaging Telescope

About Solar Ultraviolet Imaging Telescope (SUIT)

• The telescope is one of the seven payloads on Aditya-L1.
• Features
  • It is unique because it will provide full disk images of the sun in 2000 to 4000 A wavelength range which has never been obtained.
  • It will allow us to record images in this wavelength crucial for maintaining the Ozone and Oxygen content in the atmosphere of the Earth.
  • It will also measure the UV radiation hazardous for skin cancer.
  • It will address fundamental questions such as the existence of a higher-temperature atmosphere above the cooler surface of the Sun and the origin and variation of near-ultraviolet radiation and high-energy solar flares.
  • It will help in the measurement of solar radiation from Hard X-ray to Infrared, as well as in-situ measurements of particles in the solar wind, including the Sun’s magnetic field at the L1 point.
• It is expected to last five years.
• Funding: ISRO funded the initial Rs 25 crore required for the hardware, a small portion of the overall project.

Key points about Aditya-L1 Mission

• It is India's first dedicated scientific mission to study the Sun.
• The spacecraft will be placed in a halo orbit around the first Lagrange point, L1, which is 1.5 million km from the Earth towards the Sun.
• A satellite around the L1 point has the major advantage of continuously viewing the Sun without occultation/eclipses.
• Aditya-L1 carries seven payloads to observe the photosphere, chromosphere, and the outermost layers of the Sun (the corona) using electromagnetic and particle detectors.
• The satellite will be launched by a PSLV-XL launch vehicle from Sriharikota.

Miyawaki Plantation Method 

Context

• In this episode of ‘Mann ki baat’ he talked about Miyawaki plantation.
• He discussed the need to create forest in small areas using his type of plantation.
• Raafi Ramnath, A Kerala teacher, used this method to grow forest on a barren land.

Other Details

• Miyawaki technique is used by Raafi Ramnath to generate and grow forest on a barren land.
• A total of 115 varieties of trees were planted which culminated into a forest named Vidyavanam.

Miyawaki Plantation

• This technique to plant tree is named after a botanist from Japan, Akira Miyawaki.
• It was developed in the decade of 1970 with an intention of to make a dense green cover in a small area.
• In this method planting few types of indigenous trees, generally limited to 4, are planted in every square metre.
• In three years of time such trees grow tall and self-sustain themselves.

Process

• It starts with Identification of Native/local or Natural Vegetation of the area.
• Then work starts to prepare and improve the quality of soil for plantation of trees.
• 3 to 4 Saplings are planted in every square meter.
• Then the forest is mulched using compost tea and straw.

Benefits

• It helps in fighting the negative consequences of climate change.
• Help to reduce pollution levels in nearby areas by capturing dust and other particles.
• It increases the green cover of city enable residents to breathe fresh and pure air.
• It is a cost effective method to grow tree and restore green covere in cities where finding space is a problem. For instance in Mumbai, Delhi etc.
• Promotion of indigenous variety of trees for instance Bel, Anjan, Arju, Neem, Peepal and Amala, etc.
• These forests can also sustain wildlife hence these urban forest encourages new bio diversity.
• Soil fertility is also improved.
• It also helps in regulation of temperature and carbon levels due to presence of trees.

Concerns

• Sometimes no survey is done by people to identify local vegetation of the place.
• Planting non-native plant species may harm the local ecosystem and hydrology.
• It can give promotion to the practice of monoculture and hence may threaten bio diversity.
• No proper study and findings about the impact of such forests on groundwater, native biodiversity, and amount of carbon sequestration.
• Sometimes these are considered artificial forest.

Leptospirosis and Dengue Outbreaks 

Context

Leptospirosis is a bacterial infection that can be lethal and has grown increasingly common during the monsoon season. It is a serious occupational hazard for people who work in agricultural settings or in sanitary services that expose them to contaminated water.

• In addition, public health experts are raising the alarm over a potential severe dengue epidemic and stressing the necessity of increased clinical and virological surveillance. Changes in the serotypes of the dengue virus (DENV) in circulation may cause more severe and perhaps fatal symptoms.
• In 2022, 70% of dengue case samples were DENV3, with few instances of DENV4 according to the Thiruvananthapuram district in Kerala.

What is Leptospirosis?

• The bacteria Leptospira interrogans, which mostly lives in the urine of infected animals, is the main causes leptospirosis.
• The disease is spread by both domestic and wild animals, such as rats, cattle, pigs, and dogs.
• Symptoms:
• Leptospirosis symptoms can range from a minor flu-like sickness to serious illnesses that can be fatal.
• Sudden fever, chills, and headache are typical symptoms, however sometimes there are none at all.
• Organ dysfunction that affects the liver, kidneys, lungs, and brain can result from severe instances.
• Transmission:
• Leptospira is first released into the environment by infected animals' urine.
• Risky situations include direct contact with infected animal urine and indirect contact with contaminated soil and water.
• Leptospirosis is more likely to spread to those who have wounds or abrasions on their skin.
• Prevention:
• Animal infection prevention, to stop the spread of leptospirosis and lessen financial losses for farmers, hygienic animal-keeping practises, effective waste management, and better sanitation facilities are crucial.
• Controlling leptospirosis requires a "One Health" strategy, which takes into account how linked human, animal, plant, and environmental health are.
• Misconceptions About Leptospirosis:
• Leptospirosis may be spread through a variety of animal reservoir hosts, therefore the prevalent assumption that it only affects rats is untrue.

Facts about Dengue

• Dengue is a mosquito-borne tropical disease caused by the dengue virus (Genus Flavivirus), transmitted by several species of mosquito within the genus Aedes, principally Aedes aegypti.
• Additionally, this mosquito spreads the Zika and chikungunya viruses.
• Serotypes of Dengue:
• The virus that causes dengue has 4 different but closely related serotypes (separate groups within a species of microorganisms that all share a certain trait). These are DEN-1, DEN-2, DEN-3, and DEN-4.
• Symptoms:
• Severe bone, joint, and, muscle pain, pain behind the eyes, Sudden high fever, severe headaches etc.
• Dengue Vaccine:
• The first and only dengue fever DNA vaccine candidate in India has been created by scientists at India's National Centre for Biological Sciences in partnership with nine other universities in India, Africa, and the US.
• The first dengue vaccine to receive regulatory approval in the US was the CYD-TDV or Dengvaxia, which was licenced by the US Food & Drug Administration in 2019.
• In essence, Dengvaxia is a live, attenuated dengue virus that must be delivered to individuals aged 9 to 16 who have had a prior dengue infection that has been verified in a laboratory and who reside in an endemic region.
• Challenges in Vaccine Development:
• The four serotypes of the dengue virus, which are closely related, each interact with antibodies differently, making the development of an effective vaccination for the disease difficult. An ideal vaccination should prevent antibody-dependent enhancement (ADE), in which antibodies help the virus spread and cause serious illness, while still targeting all serotypes.

Manipulating Phonons for Quantum Computing

Context

• In the new study, the researchers developed an acoustic beam-splitter – a tiny device resembling a comb – that could both emit and detect individual phonons.

Phonons: Background and Description

• For the engineers who design cell phones, solar panels and computer chips, it’s increasingly important to be able to control the way heat moves through the crystalline materials — such as silicon — that these devices are based on.
• In computer and cell-phone chips, for example, one of the key limitations to increasing speed and memory is the need to dissipate the heat generated by the chips.
• To understand how heat spreads through a material, consider that heat — as well as sound — is actually the motion or vibration of atoms and molecules: Low-frequency vibrations correspond to sound, while higher frequencies correspond to heat.
• At each frequency, quantum mechanics principles dictate that the vibrational energy must be a multiple of a basic amount of energy, called a quantum, that is proportional to the frequency. Physicists call these basic levels of energy as phonons. In a sense, then, “phonon” is just a fancy word for a particle of heat.

Phonons in Crystals

• Phonons are especially relevant in the behavior of heat and sound in crystals.
• In a crystal, the atoms are neatly arranged in a uniform, repeating structure; when heated, the atoms can oscillate at specific frequencies. The bonds between the individual atoms in a crystal behave essentially like springs.
• When one of the atoms gets pushed or pulled, it sets off a wave (or phonon) travelling through the crystal.
• In practice, most materials are filled with a chaotic mix of phonons that have different frequencies and are traveling in different directions, all superimposed on each other.

Defining Phonons

Phonons are collective atomic vibrations, or quasiparticles, that act as the main heat carriers in a crystal lattice. The very quietest sounds of all consist of individual — and indivisible — phonons.

Types of Phonons

Acoustic Phonons and Optical phonons

• When the unit cell contains more than one atom, the crystal will contain two types of phonon, acoustic and optical.
• Optical phonons are excited easily by light. In acoustic phonons, both positive and negative ions swing together. In optical phonons, positive and negative phonons swing against each other.

Phonons and Photons

• The way Photons are packets of light energy; similarly, phonons are packets of vibrational energy.
• Like photons, phonons are bosons and not conserved; they can be created or destroyed in collisions.
• Unlike photons (the particles that carry light or other electromagnetic radiation), which generally don’t interact at all if they have different wavelengths, phonons of different wavelengths can interact and mix when they bump into each other, producing a different wavelength. This makes their behavior much more chaotic and thus difficult to predict and control.
• Just as photons of a given frequency can only exist at certain specific energy levels — exact multiples of the basic quanta —so, too, can phonons.
• Unlike photons, which can travel through empty space, phonons need a medium such as air or water — or in the case of the new study, the surface of an elastic material.

Extra Information

• In the quest for better ways to dissipate heat from computer chips — a key requirement as chips get faster and pack in more components — finding ways to manipulate the behavior of the phonons in those chips, so the heat can be removed easily, is the key.
• Conversely, in designing thermoelectric devices to generate electricity from temperature differences, it’s important to develop materials that can conduct electricity (the motion of electrons) easily, but block the motion of phonons (that is, heat).

Recent Research: Building Quantum Computer with Phonons

• There is a question if can we build a quantum computer whose information unit is, sound.
• According to a paper published in Science recently, it should be possible.
• Phonons can’t be permanently broken into smaller bits. But, as the new experiment showed, they can be temporarily divided into parts using quantum mechanics.
• Earlier the problem was that researchers can manipulate electrons using electric currents, magnetic fields, etc., and they can manipulate photons with mirrors, lenses, etc. – but what can they manipulate phonons with? This always remained a puzzle.
• To this end, in the new study, researchers from the University of Chicago have reported developing an acoustic beam-splitter.

Acoustic Beam-Splitter

• An acoustic beam-splitter is a tiny device resembling a comb, with 16 metal bars jutting out of it. It was placed in the middle of a 2-mm-long channel of lithium niobate.
• Each end of the channel had a superconducting qubit – a qubit whose circuit components were superconducting – that could both emit and detect individual phonons. The whole setup was maintained at an ultra-low temperature.
• If these phonons were converted to sound, their frequency would be too high for humans to hear. Each phonon in the study represented, the “collective” vibration of around one quadrillion atoms.
• The team found that these phonons interacted with the comb just like photons interact with an optical beam-splitter.
• When a phonon was emitted from the left side of the channel, it was reflected half of the time and transmitted to the right side the other half. When phonons were emitted simultaneously from the left and the right sides, they both ended up on one side (as expected).

In a nutshell,

• Acoustic beam splitter is a device that allows about half of an impinging torrent of phonons to pass through while the rest get reflected back. But when just one phonon at a time meets the beam splitter, that phonon enters a special quantum state where it goes both ways at once. The simultaneously reflected and transmitted phonon interacts with itself, in a process known as interference, to change where it ultimately ends up.
• The lab demonstration of the effect relied on sound millions of times higher in pitch than humans can hear, in a device cooled to temperatures very near absolute zero. Instead of speakers and microphones to create and hear the sound, the team used qubits, which store quantum bits of information.
• The researchers launched a phonon from one qubit toward another qubit. Along the way, the phonon encountered a beam splitter.
• Adjusting the parameters of the setup modified the way that the reflected and transmitted portions of the phonon interacted with each other. That allowed the researchers to quantum mechanically change the odds of the whole phonon turning up back at the qubit that launched the phonon or at the qubit on the other side of the beam splitter.
• A second experiment confirmed the quantum mechanical behavior of the phonons by sending phonons from two qubits to a beam splitter between them. On their own, each phonon could end up back at the qubit it came from or at the one on the opposite side of the beam splitter.
• If the phonons were timed to arrive at the beam splitter at the exact same time, though, they travel together to their ultimate destination. That is, they still unpredictably go to one qubit or the other, but they always end up at the same qubit when the two phonons hit the beam splitter simultaneously.
• If phonons followed the classical, nonquantum rules for sound, then there would be no correlation in where the two phonons go after hitting the beam splitter. The effect could serve as the basis for fundamental building blocks in quantum computers known as gates.