Dr Rajiv Desai
An Educational Blog
Undersea Optical Fiber Cable
Undersea Optical Fiber Cable: Figure above shows map of the world’s undersea communication cables. _ Section-1 Prologue: If you ask any average citizen, “where does the internet come from?” the answer you most likely get would be from space, via satellites. Wrong. Modern consumers have come to imagine the internet as something unseen in the atmosphere – an invisible “cloud” just above our heads, raining data down upon us. Because our devices aren’t tethered to any cables, many of us believe the whole thing is wireless but the reality is far more extraordinary. The vast majority of information that flows across the tens of billions of devices connected to the internet comes from the sea. Around 600 fiber-optic undersea cables carry more than 95% of all internet data. The fact that we route internet traffic through the ocean – amidst deep sea creatures and hydrothermal vents – […]
HOLOGRAM
HOLOGRAM: _____ Typical laser-lit transmission hologram ____ Prologue: Suppose you want to take a photograph of an apple. You hold a camera in front of it and, when you press the shutter button to take your picture, the camera lens opens briefly and lets light through to hit the film (in an old-fashioned camera) or the light-sensitive CCD chip (in a digital camera). All the light traveling from the apple comes from a single direction and enters a single lens, so the camera can record only a two-dimensional pattern of light, dark, and color. To be more accurate camera records wave length (color) and intensity (amplitude) of light waves. If you move your head slightly, the photograph remains same i.e. it is two dimensional. The physical world around us is three-dimensional (3D), yet traditional display devices can show only two-dimensional (2D) flat images that lack depth (i.e., the third dimension) […]
Closed-Circuit Television (CCTV)
Closed-Circuit Television (CCTV): ________ CCTV pictures showing Al Qaeda’s terrorists Mohamed Atta and Abdulaziz Alomari boarding a 6:00 a.m. flight from Portland to Boston’s Logan International Airport on September 11, 2001. _____ CCTV footages of 2015: _______ Prologue: In the past people didn’t misbehave because they thought God was watching them. Today we’ve replaced an all-seeing God with the glassy eye of the CCTV camera. A CCTV camera can operate 24 hours a day, seven days a week, and 365 days a year without a toilet break or lunch. It does not need a holiday, maternity leave and rarely goes sick. There were 25 million CCTV cameras in operation worldwide, with 2.5 million in the UK in 2002 but today the figure is doubled. Practically every major city now boasts a CCTV system aimed at, among other things, preventing, detecting and reducing crime. Increasingly these developments are mirrored in villages, […]
SCIENCE OF LANGUAGE
_ SCIENCE OF LANGUAGE: _ The figure above shows English to Gujarati mappings for consonants: _________ Prologue: Human life in its present form would be impossible and inconceivable without the use of language. To the question: “Who is speaking?” Mallarme, the French poet, answered, “Language is speaking.” The traditional conception of language is that it is, in Aristotle’s phrase, sound with meaning. Everybody uses language, but nobody knows quite how to define it. Language is arguably the defining characteristic of the human species, yet the biological basis of our ability to speak, listen and comprehend remains largely mysterious; about its evolution, we know even less. The origin of language is a widely-discussed topic. Whole doctorates have been based on it, thousands of books have been written on it, and scholars continue to argue about how and why it first emerged. Many animals can communicate effectively with one another but humans […]
THE SLEEP
_ THE SLEEP _ Prologue: When I was working as a medical specialist in Saudi Arabia, my duty time was 7.30 am to 5 pm and additional calls at night. If I woke up at 2 am to treat a serious patient and finished work at 3 am, technically speaking I worked 1 hour extra. My Saudi boss used to say that I can come 1 hour late next day at 8.30 am as I worked previous night for 1 hour extra. It is stupid to say the least and cruel to say the most. The issue is not 1 hour night disturbance but you do not get good sleep after being woken up at midnight and your next day is spoiled due to day-time sleepiness. I am sure that medical professionals, police, military, fire brigade etc will agree with me. Even today, I am the only physician in the […]
