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Sonar Technology, Cloud Seeding, Aerial Seeding, Silage, Opah Fish

India to Export Sonars Technology

India is looking to export indigenously developed hull-mounted sonars and negotiations are at an advanced stage with the navies of three to four friendly nations.


SONAR (Sound Navigation and Ranging)

  • Used to detect underwater targets + for exploring and mapping the ocean
  • Used for underwater surveillance, communication and marine navigation
  • Sound waves travel farther in water than radar and light waves


Active Sonar
  • Emit an acoustic signal, if an object is in the path of the sound pulse, the sound bounces off the object and returns an “echo” to the sonar transducer, which measures the strength of the signal.
  • By determining the time between the emission of the sound pulse and its reception, the transducer can determine the range and orientation of the object.


Passive Sonar
  • passive sonar does not emit its own signal but only detects sound waves coming towards it
  • Multiple passive sonar devices may allow for triangulation of a sound source.
  • an advantage for military vessels that do not want to be found or for scientific missions that concentrate on quietly “listening” to the ocean


Effect on Marine Animals
  • use of active sonar can lead to mass stranding of marine mammals viz. Beaked whales
  • Some marine animals, such as whales and dolphins, use echolocation systems, sometimes called biosonar to locate predators and prey. It is conjectured that active sonar transmitters could confuse these animals and interfere with basic biological functions such as feeding and mating.
  • High intensity sonar sounds can create a small temporary shift in the hearing threshold of some fish.


Cloud Seeding 

The Karnataka State government has decided to take up cloud seeding to overcome the crisis in the agricultural sector owing to deficient rainfall this year

  • Cloud seeding, a form of weather modification, is an attempt to change the amount or type of precipitation that falls from clouds, by dispersing substances into the air that serve as cloud condensation or ice nuclei.
  • Chemicals used: Silver iodide, potassium iodide and dry ice (solid carbon dioxide). Liquid propane 


Cloud Seeding


  • To increase rainfall in a particular area.
  • To prevent hail and fog


Aerial Seeding 

  • Aerial seeding is a technique of sowing seeds using helicopters and aeroplanes to scatter them.
  • Andhra Pradesh govt. launched aerial seeding of nearly 1,500 hectares of degraded forest on hill slopes in Guntur and Krishna districts that are not suitable for traditional methods of sowing.
  • The Gandhi Hill in AP did not have any greenery a few decades ago, but today the entire hill is covered by trees because of aerial seeding followed up by protection.


  • Large wildfires can destroy large areas of plant life resulting in erosion hazards.
  • Arial seeding may quickly and effectively reduce erosion hazards and suppress growth of invasive plant species.
  • Can be used where terrain is extremely rocky or at high elevations or otherwise inaccessible
  • Efficient coverage of a large area in the least amount of time



  • Silage, a green fodder compacted in air tight conditions to be used as substitute for green fodder during the lean period for livestock


  • Potential fodder for livestock living in the rain shadow areas
  • Can be used as alternative during dry period
  • Potential to increase the milk yield


Tamilnadu government has embarked upon a programme to popularise silage making. Scientists of Tamil Nadu Veterinary University Training and Research Centre at Karur demonstrated the silage making by using repol polypropylene (silage bags)


silage preparation


Method of Silage Preparation
  • Green grass mass is stored in large sacks made from polythene
  • Once the bag is filled, the material is pressed to remove the air and thereby preventing decomposition.
  • After that it is fermented by adding diluted molasses and preserved for 60 days at appropriate moisture levels


Opah, the world’s first fully warm-blooded fish species

  • Found in the deep waters, Opah fish has developed an internal heat exchange system within its gills to conserve the warmth and it raises its temperature by flapping its fins
  • Mechanism is similar to that used by mammals and birds, which are known as endothermsfor their ability to maintain body temperature independent of the environment.
  • While tuna and some sharks can warm certain parts of their bodies, such as their brains and eyes, fish are generally classed among cold-blooded animals, known as


Parthenogenesis (Virgin Birth – Reproduction without Mating)

  • There have been a number of cases in reptiles, birds and sharks of ‘virgin birth’ in captivity
  • In this a female’s egg cell can develop into a baby without being fertilized by a male’s sperm cell
  • It is the first time this phenomenon has been seen in a vertebrate viz. critically endangered sawfish


Smalltooth sawfish
  • Also known as the wide sawfish
  • It is found in shallow tropical and subtropical waters in coastal parts of the Atlantic, including the Mediterranean


Ebola Vaccine Developed 

  • Developed by Public Health Agency of Canada
  • Trial result show 100% efficacy.
  • How it works: A dummy virus (vesicular stomatitis virus, or VSV) was designed with diluted elements of Ebola. As the risk-free virus enters a human body, it alarms the immune system, which launches a scathing attack on the intruder, killing it along with the deadly Ebola virus.


CSIR published whole genome sequence of Tulsi (Holi Basil / Ocimum sanctum)

  • It is first step to understand and unravel the secrets of this mother of all herbs.
  • It will help in providing scientific validity to the traditional claims of its utility in diverse medicinal usage
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1 Comment

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