Botswana: UB, Chinese Universities Collaborate in Research

[Botswana Daily News] Gaborone -A delegation from Fujian Medical University of China paid a courtesy call on the University of Botswana (UB) acting vice chancellor, Professor Kgomotso Moahi on Tuesday to discuss progress made in the implementation of a Memorandum of Understanding (MoU) they signed in October 2015.

7 In 10 Indonesian Children Exposed To Dengue

In a study conducted on more than 3,000 Indonesian children from ages one to 18, nearly 70 percent tested positive for dengue antibodies, an indication that they have been infected before.

Ultra-thin camera design doesn’t need a lens

Traditional cameras—even those on the thinnest of cell phones—cannot be truly flat due to their optics: lenses that require a certain shape and size in order to function.

A new camera design replaces the lenses with an ultra-thin optical phased array (OPA) that does computationally what lenses do using large pieces of glass: it manipulates incoming light to capture an image.

OPA on penny for scale
OPA on penny for scale. (Credit: Caltech)
lensless camera prototype
(Credit: Caltech)

Lenses have a curve that bends the path of incoming light and focuses it onto a piece of film or, in the case of digital cameras, an image sensor. The OPA has a large array of light receivers, each of which can individually add a tightly controlled time delay (or phase shift) to the light it receives, enabling the camera to selectively look in different directions and focus on different things.

“Here, like most other things in life, timing is everything. With our new system, you can selectively look in a desired direction and at a very small part of the picture in front of you at any given time, by controlling the timing with femto-second—quadrillionth of a second—precision,” says Ali Hajimiri, professor of electrical engineering and medical engineering at California Institute of Technology and principal investigator of a paper in OSA Technical Digest.

“We’ve created a single thin layer of integrated silicon photonics that emulates the lens and sensor of a digital camera, reducing the thickness and cost of digital cameras. It can mimic a regular lens, but can switch from a fish-eye to a telephoto lens instantaneously—with just a simple adjustment in the way the array receives light.”

Camera prototype is thinner than a dime

Phased arrays, which are used in wireless communication and radar, are collections of individual transmitters, all sending out the same signal as waves. These waves interfere with each other constructively and destructively, amplifying the signal in one direction while canceling it out elsewhere. So, an array can create a tightly focused beam of signal, which can be steered in different directions by staggering the timing of transmissions made at various points across the array.

A similar principle is used in reverse in an optical phased array receiver, which is the basis for the new camera. Light waves that are received by each element across the array cancel each other from all directions, except for one. In that direction, the waves amplify each other to create a focused “gaze” that can be electronically controlled.

“What the camera does is similar to looking through a thin straw and scanning it across the field of view. We can form an image at an incredibly fast speed by manipulating the light instead of moving a mechanical object,” says graduate student Reza Fatemi, the paper’s lead author.

Last year, Hajimiri’s team rolled out a one-dimensional version of the camera that was capable of detecting images in a line, such that it acted like a lensless barcode reader but with no mechanically moving parts.

New camera uses just 1 photon per pixel

This year’s advance was to build the first two-dimensional array capable of creating a full image. This first 2D lensless camera has an array composed of just 64 light receivers in an 8 by 8 grid. The resulting image has low resolution—but the system represents a proof of concept for a fundamental rethinking of camera technology, researchers say.

“The applications are endless,” says graduate student and coauthor Behrooz Abiri. “Even in today’s smartphones, the camera is the component that limits how thin your phone can get. Once scaled up, this technology can make lenses and thick cameras obsolete. It may even have implications for astronomy by enabling ultra-light, ultra-thin enormous flat telescopes on the ground or in space.”

“The ability to control all the optical properties of a camera electronically using a paper-thin layer of low-cost silicon photonics without any mechanical movement, lenses, or mirrors, opens a new world of imagers that could look like wallpaper, blinds, or even wearable fabric,” says Hajimiri.

The team will next work on scaling up the camera by designing chips that enable much larger receivers with higher resolution and sensitivity.

Source: Caltech

The post Ultra-thin camera design doesn’t need a lens appeared first on Futurity.

Evidence Is Encouraging but Insufficient That Three Interventions Might Slow Cognitive Decline and the Onset of Dementia

Cognitive training, blood pressure management for people with hypertension, and increased physical activity all show modest but inconclusive evidence that they can help prevent cognitive decline and dementia, but there is insufficient evidence to support a public health campaign encouraging their adoption, says a new report from the National Academies. Additional research is needed to further understand and gain confidence in their effectiveness. Although the strength of evidence does not warrant aggressive public health campaigns, it does suggest that information should be made available to the interested public. It is appropriate to provide accurate information about the potential impact of these three interventions where people can access it, such as on websites, as well as for public health practitioners and health care providers to include mention of the potential cognitive benefits of these interventions when promoting their adoption for the prevention or control of other diseases and conditions. Read More

NASA finds 10 more habitable, Earth-like exoplanets

NASA’s planet-hunting Kepler Space Telescope mission has resulted in the discovery of more than 200 new candidates since the last time data was released by the US space agency, including 10 nearly-Earth sized, potentially habitable new worlds, various media outlets have reported.

During a briefing held on Monday, Kepler scientists revealed that the latest round of discoveries brings the overall number of candidate planets discovered by the telescope to 4,034, according to Space.com. Of those, 2,335 have been confirmed by follow-up observations.

In addition, the 10 new, nearly-Earth-sized candidate planets found to be orbiting in their star’s habitable zones (meaning that they were the correct distance for liquid water to pool and persist on the surface of a rocky planet) boost the number of such worlds discovered thus far to 50. Of those discoveries, 30 have been confirmed to date, the agency said during its briefing.

In a statement, NASA called Monday’s announcement “the most comprehensive and detailed catalog release of candidate exoplanets… from Kepler’s first four years of data. It’s also the final catalog from the spacecraft’s view of the patch of sky in the Cygnus constellation.”

Transit method used to discover 4,000 potential new worlds

Launched in 2009, Kepler had been monitoring the roughly 200,000 stars in Cygnus, a northern constellation resting on the plane of the Milky Way, during the initial phase of its mission, the Washington Post noted. Its goal was to collect demographic data about our galaxy: for instance, to learn how many stars are similar to our sun, or how many planets could support biological life.

Kepler, which NASA said has discovered more than 80% of all known confirmed exoplanets and candidate planets identified to date, uses what it known as the transit method, which means that it tracks stars over extended periods of time looking for brief periods of dimming. Those periods of dimming, they explained, indicate a potential planet crossing between the star and Earth.

According to Space.com, the telescope detected about 34,000 signals while studying the Cygnus constellation, indicating a combination of transiting planets and background noise that may have come from either the star being studied or the instrument itself. Additional analysis whittled that figure down to approximately 4,000 candidates, including the 50 Earth-like habitable planets.

Analysis also uncovers ‘new division’ in exoplanet ‘family tree’

Furthermore, the Kepler scientists revealed that there was a surprising dichotomy when it came to smaller worlds: rather than coming in a variety of different types, they primarily fell into one of just two different categories – small, Earth-like worlds or gaseous Neptune-like planets.

“This is a major new division in the family tree of exoplanets, somewhat analogous to the discovery that mammals and lizards are separate branches on the tree of life,” Benjamin Fulton, who is a researcher at the University of Hawaii in Manoa and California Institute of Technology (Caltech), explained at Monday’s briefing, according to Space.com.

Fulton and his colleagues used the Keck Observatory in Hawaii to determine the size of 1,300 stars measured by Kepler, then used that data to calculate the size of the planet candidates the telescope had detected. While they anticipated finding a range of worlds between one and four times that of Earth, they would that most were either rocky planets up to 1.75 times as large as our planer, or dense gas worlds (mini-Neptunes) 2.0 to 3.5 the size of the Earth.

“It’s amazing the things that Kepler has found,” said Kepler scientist Susan Thompson of the SETI Institute in California.  “It has shown us these terrestrial worlds, and we still have all this work to do to really understand how common Earths are in the galaxy. I’m really excited to see what people are going to do with this catalog.”

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Image credit: NASA JPL/Caltech

The post NASA finds 10 more habitable, Earth-like exoplanets appeared first on Redorbit.

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