10 best 3D map photogrammetry software reviewed. Top drone mapping and modelling solutions from DroneDeploy, Open Drone Map, Pix4D, PhotoScan, Precision Mapper, AutoDesk plus more.
An epic lunar laser experiment is still going strong, five decades after the Apollo astronauts set it up on the surface.
The moonwalking crew of Apollo 11, which landed on the moon 50 years ago this month, put special retroreflectors on the lunar surface, as did the later crews of Apollo 14 and 15, in 1971. (Another retroreflector, built by the French, sits on the Soviet Lunokhod 2 rover that landed without a crew in 1973.)
Time is the indefinite continued progress of existence and events that occur in an apparently irreversible succession from the past, through the present, to the future.[1][2][3] Time is a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in the conscious experience.[4][5][6][7] Time is often referred to as a fourth dimension, along with three spatial dimensions.[8]
Time has long been an important subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars.[2][6][7][9][10][11] Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems.[12][13][14]
Time in physics is unambiguously operationally defined as “what a clock reads”.[6][15][16] See Units of Time is one of the seven fundamental physical quantities in both the International System of Units and International System of Quantities. Time is used to define other quantities – such as velocity – so defining time in terms of such quantities would result in circularity of definition.[17] An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life.
Scientists have achieved the first realization of a terahertz quantum cascade laser operating without cryogenic cooling. This feat heralds the widespread use of these devices in practical applications.
Are made up of many thin layers of semiconductor. An injected electron makes a small energy transition as it moves from one layer to the next, emitting light on each cascade. Because the energy steps are small, quantum cascade lasers can produce long-wavelength mid-infrared or terahertz radiation.
While more people and places are switching to energy-saving LED light bulbs, a California company has found a way to turn them into smart networks that can collect and feed data. However, the new technological opportunities are also raising privacy concerns, reports CBS News’ Bill Whitaker.
For example, should you find yourself in terminal “B” at Newark airport, look up. Those aren’t just new lights. They’re smart lights — a sophisticated array of LED fixtures with built-in sensors and cameras connected over a wireless network. They monitor security and the flow of foot traffic.
“Newark’s primarily interested in energy saving,” said Hugh Martin, president of Sensity, the Silicon Valley company that developed the smart lights at Newark and also a parking garage in San Jose.
I call them “BATS”.
Can bacteria generate radio waves?
On the face of it, this seems an unlikely proposition. Natural sources of radio waves include lightning, stars and pulsars while artificial sources include radar, mobile phones and computers. This is a diverse list. So it’s hard to see what these things might have in common with bacteria that could be responsible for making radio waves.
Continue reading “How Bacteria Could Generate Radio waves” »
A study in the British Medical Journal this week found a link between regular consumption of sugary drinks and cancer. Here’s what experts want you to know.
Optogenetic approaches are widely used to manipulate neural activity and assess the consequences for brain function. Here, a technique is outlined that upon in vivo expression of the optical activator Channelrhodopsin, allows for ex vivo analysis of synaptic properties of specific long range and local neural connections in fear-related circuits.
