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Harvesting renewable energy from the sun and outer space at the same time -- ScienceDaily

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Scientists at Stanford University have demonstrated for the first time that heat from the sun and coldness from outer space can be collected simultaneously with a single device. Their research, published November 8 in the journal Joule, suggests that devices for harvesting solar and space energy will not compete for land space and can actually help each other function more efficiently.

Renewable energy is increasingly popular as an economical and efficient alternative to fossil fuels, with solar energy topping charts as the worldwide favorite. But there is another powerful energy source overhead that can perform just the opposite function -- outer space.

"It is widely recognized that the sun is a perfect heat source nature offers human beings on Earth," says Zhen Chen, the first author of the study, who is a former postdoctoral research associate at Stanford in the group of Shanhui Fan and is currently a professor at the Southeast University of China. "It is less widely recognized that nature also offers human beings outer space as a perfect heat sink."

Objects give off heat as infrared radiation -- a form of light invisible to the human eye. Most of this radiation is reflected back to Earth by particles in the atmosphere, but some of it escapes into space, allowing surfaces that emit enough radiation within the infrared range to drop below the temperature of their surroundings. Radiative cooling technology reflects copious amounts of infrared light, providing an air conditioning alternative that doesn't emit greenhouse gases. It may also help improve solar cell efficiency, which decreases the hotter solar cells become -- if only the two technologies can coexist peacefully on one rooftop.

Chen and his colleagues developed a device combining radiative cooling with solar absorption technology. The device consists of a germanium solar absorber on top of a radiative cooler with silicon nitride, silicon, and aluminum layers enclosed in a vacuum to minimize unwanted heat loss. Both the solar absorber and the atmosphere are transparent in the mid-infrared range of 8-13 microns, offering a channel for infrared radiation from the radiative cooler to pass through to outer space. The team demonstrated that the combined device can simultaneously provide 24?C in solar heating and 29?C in radiative cooling, with the solar absorber improving the radiative cooler's performance by blocking heat from the sun.

"On a rooftop, we imagine a photovoltaic cell can supply electricity while the radiative cooler can cool down the house on hot summer days," says Chen.

While this technology appears promising, Chen believes there is still plenty of work to do before it can be scaled up for commercial use. While the vacuum enveloping the device could be scaled up with relative ease, the infrared-transparent window made from zinc selenide is still too costly, and the solar absorber and radiative cooler could be designed from cheaper high-performing materials as well. Chen thinks it is also important to test the use of photovoltaic cells in the place of a solar absorber -- an idea which has yet to be demonstrated. But in spite of all these practical challenges, the team believes this research demonstrates that renewable energy has even more rooftop potential than previously thought.

"I think this technology could potentially revolutionize the current solar cell technology," says Chen. "If our concept is demonstrated and scaled up, the future solar cell will have two functions in one: electricity and cooling."

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Materials provided by Cell Press. Note: Content may be edited for style and length.

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If I understand it correctly the really clever part of this setup is that this radiates heat out in infrared bands Earth's atmosphere absorbs poorly, which means that the energy being radiated out in those bands will just go straight out to space instead of just heating the air around the device.
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Secret CIA Document Shows Plan to Test Drugs on Prisoners

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Thanks to an ACLU victory in federal court, we know much more about how CIA doctors violated the medical oath to “do no harm.”

One of the most important lessons of the CIA’s torture program is the way it corrupted virtually every individual and institution associated with it. Over the years, we have learned how lawyers twisted the law and psychologists betrayed their ethical obligations in order to enable the brutal and unlawful torture of prisoners.

Now we’ve won the release of a 90-page account of the CIA’s Office of Medical Services role in the CIA torture program — a secret history written by the top CIA medical official, whose identity remains classified.

The history reveals that CIA doctors were hunting for a “truth serum” to use on prisoners as part of a previously secret effort called Project Medication. The CIA studied records of old Soviet drug experiments as well as the CIA’s notorious and discredited MK-Ultra program, which involved human experimentation with LSD and other drugs on unwitting subjects. The CIA doctors involved in Project Medication wanted to use Versed, a psychoactive drug similar to some of those used in MK-Ultra, on prisoners.

The CIA ignored lessons from its own history. After MK-Ultra was shut down, the CIA director testified in 1977, “It is totally abhorrent to me to think of using humans as guinea pigs.” But decades later, the agency decided to experiment on humans again, testing pseudoscientific theories of “learned helplessness” on its prisoners.

While Project Medication never got off the ground, CIA medical professionals remained critical participants in experimenting with torture. Just like the government lawyers who tried to give unlawful torture a veneer of legality, the secret history reveals that CIA doctors were “indispensable” to the effort of “legitimizing the program.”

Perhaps the most striking element of the document is the CIA doctors’ willful blindness to the truth of what they were doing. CIA doctors decided that waterboarding actually “provided periodic relief” to a prisoner because it was a break from days of standing sleep deprivation. Similarly, CIA doctors decided that when a different prisoner was stuffed into a coffin-sized box, this provided a “relatively benign sanctuary” from other torture methods. CIA doctors described yet another prisoner — who cried, begged, pleaded, vomited, and required medical resuscitation after being waterboarded — as “amazingly resistant to the waterboard.” Incredibly, CIA doctors concluded that the torture program was “reassuringly free of enduring physical or psychological effects.”

The truth is that CIA torture left a legacy of broken bodies and traumatized minds. Today, with a president who has vocally supported torture and a new CIA director who was deeply complicit in torturing prisoners, it’s more important than ever to expose the crimes of the past. Recognizing the roles played by the lawyers, doctors, and psychologists who enabled torture is critical to making sure it never happens again.

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"CIA doctors decided that waterboarding actually “provided periodic relief” to a prisoner because it was a break from days of standing sleep deprivation."

Jesus Fucking Christ. Really? Sacrificing morality for ideology, or did these people never have a sense of morality to begin with? How do you become a doctor, and then participate in this? How broken do you have to be?

This is a serious breach of trust and the Hippocratic Oath, and these people need to be brought to account.
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Delay, Deny and Deflect: How Facebook’s Leaders Fought Through Crisis

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In the final months of Mr. Trump’s presidential campaign, Russian agents escalated a yearlong effort to hack and harass his Democratic opponents, culminating in the release of thousands of emails stolen from prominent Democrats and party officials.

Facebook had said nothing publicly about any problems on its own platform. But in the spring of 2016, a company expert on Russian cyberwarfare spotted something worrisome. He reached out to his boss, Mr. Stamos.

Mr. Stamos’s team discovered that Russian hackers appeared to be probing Facebook accounts for people connected to the presidential campaigns, said two employees. Months later, as Mr. Trump battled Hillary Clinton in the general election, the team also found Facebook accounts linked to Russian hackers who were messaging journalists to share information from the stolen emails.

Mr. Stamos, 39, told Colin Stretch, Facebook’s general counsel, about the findings, said two people involved in the conversations. At the time, Facebook had no policy on disinformation or any resources dedicated to searching for it.

Mr. Stamos, acting on his own, then directed a team to scrutinize the extent of Russian activity on Facebook. In December 2016, after Mr. Zuckerberg publicly scoffed at the idea that fake news on Facebook had helped elect Mr. Trump, Mr. Stamos — alarmed that the company’s chief executive seemed unaware of his team’s findings — met with Mr. Zuckerberg, Ms. Sandberg and other top Facebook leaders.

Ms. Sandberg was angry. Looking into the Russian activity without approval, she said, had left the company exposed legally. Other executives asked Mr. Stamos why they had not been told sooner.

Still, Ms. Sandberg and Mr. Zuckerberg decided to expand on Mr. Stamos’s work, creating a group called Project P, for “propaganda,” to study false news on the site, according to people involved in the discussions. By January 2017, the group knew that Mr. Stamos’s original team had only scratched the surface of Russian activity on Facebook, and pressed to issue a public paper about their findings.

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Seeing in the Dark on Pixel Phones

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Posted by Marc Levoy, Distinguished Engineer and Yael Pritch, Staff Software Engineer

Night Sight is a new feature of the Pixel Camera app that lets you take sharp, clean photographs in very low light, even in light so dim you can't see much with your own eyes. It works on the main and selfie cameras of all three generations of Pixel phones, and does not require a tripod or flash. In this article we'll talk about why taking pictures in low light is challenging, and we'll discuss the computational photography and machine learning techniques, much of it built on top of


, that make Night Sight work.

Why is Low-light Photography Hard?

Anybody who has photographed a dimly lit scene will be familiar with

image noise

, which looks like random variations in brightness from pixel to pixel. For smartphone cameras, which have small lenses and sensors, a major source of noise is the natural variation of the number of photons entering the lens, called

shot noise

. Every camera suffers from it, and it would be present even if the sensor electronics were perfect. However, they are not, so a second source of noise are random errors introduced when converting the electronic charge resulting from light hitting each pixel to a number, called

read noise

. These and other sources of randomness contribute to the overall

signal-to-noise ratio

(SNR), a measure of how much the image stands out from these variations in brightness. Fortunately, SNR rises with the square root of exposure time (or faster), so taking a longer exposure produces a cleaner picture. But it’s hard to hold still long enough to take a good picture in dim light, and whatever you're photographing probably won't hold still either.

In 2014 we introduced


, a computational photography technology that improves this situation by capturing a burst of frames, aligning the frames in software, and merging them together. The main purpose of HDR+ is to improve dynamic range, meaning the ability to photograph scenes that exhibit a wide range of brightnesses (like sunsets or backlit portraits). All generations of Pixel phones use HDR+. As it turns out, merging multiple pictures also reduces the impact of shot noise and read noise, so it improves SNR in dim lighting. To keep these photographs sharp even if your hand shakes and the subject moves, we use short exposures. We also reject pieces of frames for which we can't find a good alignment. This allows HDR+ to produce sharp images even while collecting more light.

How Dark is Dark?

But if capturing and merging multiple frames produces cleaner pictures in low light, why not use HDR+ to merge dozens of frames so we can effectively see in the dark? Well, let's begin by defining what we mean by "dark". When photographers talk about the light level of a scene, they often measure it in lux. Technically, lux is the amount of light arriving at a surface per unit area, measured in lumens per meter squared. To give you a feeling for different lux levels, here's a handy table:

Smartphone cameras that take a single picture begin to struggle at 30 lux. Phones that capture and merge several pictures (as HDR+ does) can do well down to 3 lux, but in dimmer scenes don’t perform well (more on that below), relying on using their flash. With Night Sight, our goal was to improve picture-taking in the regime between 3 lux and 0.3 lux, using a smartphone, a single shutter press, and no LED flash. To make this feature work well includes several key elements, the most important of which is to capture more photons.

Capturing the Data

While lengthening the exposure time of each frame increases SNR and leads to cleaner pictures, it unfortunately introduces two problems. First, the default picture-taking mode on Pixel phones uses a


(ZSL) protocol, which intrinsically limits exposure time. As soon as you open the camera app, it begins capturing image frames and storing them in a circular buffer that constantly erases old frames to make room for new ones. When you press the shutter button, the camera sends the most recent 9 or 15 frames to our



Super Res Zoom

software. This means you capture exactly the moment you want — hence the name zero-shutter-lag. However, since we're displaying these same images on the screen to help you aim the camera, HDR+ limits exposures to at most 66ms no matter how dim the scene is, allowing our viewfinder to keep up a display rate of at least 15 frames per second. For dimmer scenes where longer exposures are necessary, Night Sight uses


(PSL), which waits until after you press the shutter button before it starts capturing images. Using PSL means you need to hold still for a short time after pressing the shutter, but it allows the use of longer exposures, thereby improving SNR at much lower brightness levels.

The second problem with increasing per-frame exposure time is motion blur, which might be due to handshake or to moving objects in the scene. Optical image stabilization (OIS), which is present on Pixel 2 and 3, reduces handshake for moderate exposure times (up to about 1/8 second), but doesn’t help with longer exposures or with moving objects. To combat motion blur that OIS can’t fix, the Pixel 3’s default picture-taking mode uses “motion metering”, which consists of using

optical flow

to measure recent scene motion and choosing an exposure time that minimizes this blur. Pixel 1 and 2 don’t use motion metering in their default mode, but all three phones use the technique in Night Sight mode, increasing per-frame exposure time up to 333ms if there isn't much motion. For Pixel 1, which has no OIS, we increase exposure time less (for the selfie cameras, which also don't have OIS, we increase it even less). If the camera is being stabilized (held against a wall, or using a tripod, for example), the exposure of each frame is increased to as much as one second. In addition to varying per-frame exposure, we also vary the number of frames we capture, 6 if the phone is on a tripod and up to 15 if it is handheld. These frame limits prevent user fatigue (and the need for a cancel button). Thus, depending on which Pixel phone you have, camera selection, handshake, scene motion and scene brightness, Night Sight captures 15 frames of 1/15 second (or less) each, or 6 frames of 1 second each, or anything in between.


Here’s a concrete example of using shorter per-frame exposures when we detect motion:

And here’s an example of using longer exposure times when we detect that the phone is on a tripod:

Alignment and Merging

The idea of averaging frames to reduce imaging noise is as old as digital imaging. In astrophotography it's called

exposure stacking

. While the technique itself is straightforward, the hard part is getting the alignment right when the camera is handheld. Our efforts in this area began with an app from 2010 called


. This app captured pictures continuously, aligned and merged them in real time at low resolution, and displayed the merged result, which

steadily became cleaner as you watched


Night Sight uses a similar principle, although at full sensor resolution and not in real time. On Pixel 1 and 2 we use

HDR+'s merging algorithm

, modified and re-tuned to strengthen its ability to detect and reject misaligned pieces of frames, even in very noisy scenes. On Pixel 3 we use

Super Res Zoom

, similarly re-tuned, whether you zoom or not. While the latter was developed for super-resolution, it also works to reduce noise, since it averages multiple images together. Super Res Zoom produces better results for some nighttime scenes than HDR+, but it requires the faster processor of the Pixel 3.

By the way, all of this happens on the phone in a few seconds. If you're quick about tapping on the icon that brings you to the filmstrip (wait until the capture is complete!), you can watch your picture "develop" as HDR+ or Super Res Zoom completes its work.

Other Challenges

Although the basic ideas described above sound simple, there are some gotchas when there isn't much light that proved challenging when developing Night Sight:

1. Auto white balancing (AWB) fails in low light.

Humans are good at

color constancy

— perceiving the colors of things correctly even under colored illumination (or when wearing sunglasses). But that process breaks down when we take a photograph under one kind of lighting and view it under different lighting; the photograph will look tinted to us. To correct for this perceptual effect, cameras adjust the colors of images to partially or completely compensate for the dominant color of the illumination (sometimes called

color temperature

), effectively shifting the colors in the image to make it seem as if the scene was illuminated by neutral (white) light. This process is called

auto white balancing


The problem is that white balancing is what mathematicians call an

ill-posed problem

. Is that snow really blue, as the camera recorded it? Or is it white snow illuminated by a blue sky? Probably the latter. This ambiguity makes white balancing hard. The AWB algorithm used in non-Night Sight modes is good, but in very dim or strongly colored lighting (think sodium vapor lamps), it’s hard to decide what color the illumination is.

To solve these problems, we developed a

learning-based AWB algorithm

, trained to discriminate between a well-white-balanced image and a poorly balanced one. When a captured image is poorly balanced, the algorithm can suggest how to shift its colors to make the illumination appear more neutral. Training this algorithm required photographing a diversity of scenes using Pixel phones, then hand-correcting their white balance while looking at the photo on a color-calibrated monitor. You can see how this algorithm works by comparing the same low-light scene captured using two ways using a Pixel 3:

2. Tone mapping of scenes that are too dark to see.

The goal of Night Sight is to make photographs of scenes so dark that you can't see them clearly with your own eyes — almost like a super-power! A related problem is that in very dim lighting humans stop seeing in color, because the

cone cells

in our retinas stop functioning, leaving only the rod cells, which can't distinguish different wavelengths of light. Scenes are still colorful at night; we just can't see their colors. We want Night Sight pictures to be colorful - that's part of the super-power, but another potential conflict. Finally, our rod cells have low spatial acuity, which is why things seem indistinct at night. We want Night Sight pictures to be sharp, with more detail than you can really see at night.

For example, if you put a DSLR camera on a tripod and take a very long exposure — several minutes, or stack several shorter exposures together — you can make nighttime look like daytime. Shadows will have details, and the scene will be colorful and sharp. Look at the photograph below, which was captured with a DSLR; it must be night, because you can see the stars, but the grass is green, the sky is blue, and the moon casts shadows from the trees that look like shadows cast by the sun. This is a nice effect, but it's not always what you want, and if you share the photograph with a friend, they'll be confused about when you captured it.

Artists have known for centuries how to make a painting look like night; look at the example below.


We employ some of the same tricks in Night Sight, partly by throwing an


into our tone mapping. But it's tricky to strike an effective balance between giving you “magical super-powers” while still reminding you when the photo was captured. The photograph below is particularly successful at doing this.

How Dark can Night Sight Go?

Below 0.3 lux, autofocus begins to fail. If you can't find your keys on the floor, your smartphone can't focus either. To address this limitation we've added two manual focus buttons to Night Sight on Pixel 3 - the "Near" button focuses at about 4 feet, and the "Far" button focuses at about 12 feet. The latter is the

hyperfocal distance

of our lens, meaning that everything from half of that distance (6 feet) to infinity should be in focus. We’re also working to improve Night Sight’s ability to autofocus in low light. Below 0.3 lux you can still take amazing pictures with a smartphone, and even do astrophotography as this

blog post

demonstrates, but for that you'll need a tripod, manual focus, and a 3rd party or custom app written using Android's Camera2 API.

How far can we take this? Eventually one reaches a light level where read noise swamps the number of photons gathered by that pixel. There are other sources of noise, including dark current, which increases with exposure time and varies with temperature. To avoid this biologists know to cool their cameras well below zero (Fahrenheit) when imaging weakly fluorescent specimens — something we don’t recommend doing to your Pixel phone! Super-noisy images are also hard to align reliably. Even if you could solve all these problems, the wind blows, the trees sway, and the stars and clouds move. Ultra-long exposure photography is hard.

How to Get the Most out of Night Sight

Night Sight not only takes great pictures in low light; it's also fun to use, because it takes pictures where you can barely see anything. We pop up a “chip” on the screen when the scene is dark enough that you’ll get a better picture using Night Sight, but don't limit yourself to these cases. Just after sunset, or at concerts, or in the city, Night Sight takes clean (low-noise) shots, and makes them brighter than reality. This is a "look", which seems magical if done right. Here are some


of Night Sight pictures, and some

A/B comparisons

, mostly taken by our coworkers. And here are some tips on using Night Sight:

- Night Sight can't operate in complete darkness, so pick a scene with some light falling on it.
- Soft, uniform lighting works better than harsh lighting, which creates dark shadows.
- To avoid lens flare artifacts, try to keep very bright light sources out of the field of view.
- To increase exposure, tap on various objects, then move the exposure slider. Tap again to disable.
- To decrease exposure, take the shot and darken later in Google’s Photos editor; it will be less noisy.
- If it’s so dark the camera can’t focus, tap on a high-contrast edge, or the edge of a light source.
- If this won’t work for your scene, use the Near (4 feet) or Far (12 feet) focus buttons (see below).
- To maximize image sharpness, brace your phone against a wall or tree, or prop it on a table or rock.
- Night Sight works for selfies too, as in the A/B album, with optional illumination from the screen itself.

Night Sight works best on Pixel 3. We’ve also brought it to Pixel 2 and the original Pixel, although on the latter we use shorter exposures because it has no optical image stabilization (OIS). Also, our learning-based white balancer is trained for Pixel 3, so it will be less accurate on older phones. By the way, we brighten the viewfinder in Night Sight to help you frame shots in low light, but the viewfinder is based on 1/15 second exposures, so it will be noisy, and isn't a fair indication of the final photograph. So take a chance — frame a shot, and press the shutter. You'll often be surprised!

Night Sight was a collaboration of several teams at Google. Key contributors to the project include: from the Gcam team Charles He, Nikhil Karnad, Orly Liba, David Jacobs, Tim Brooks, Michael Milne, Andrew Radin, Navin Sarma, Jon Barron, Yun-Ta Tsai, Jiawen Chen, Kiran Murthy, Tianfan Xue, Dillon Sharlet, Ryan Geiss, Sam Hasinoff and Alex Schiffhauer; from the Super Res Zoom team Bart Wronski, Peyman Milanfar and Ignacio Garcia Dorado; from the Google camera app team Gabriel Nava, Sushil Nath, Tim Smith , Justin Harrison, Isaac Reynolds and Michelle Chen.

1 By the way, the exposure time shown in Google Photos (if you press "i") is per-frame, not total time, which depends on the number of frames captured. You can get some idea of the number of frames by watching the animation while the camera is collecting light. Each tick around the circle is one captured frame.
2 For a wonderful analysis of these techniques, look at von Helmholtz, "On the relation of optics to painting" (1876).

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Pixel Night Sight also works in daylight, reducing noise and boosting resolution

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Turns out that Google's new Night Sight mode for Pixels, formally released just earlier today, has a bit of non-night utility. In a bit of a twist, you can use it in the daytime as well for "denoising and resolution improvements" inherited from another Google Camera feature: Super Res Zoom. The results demonstrated look pretty good, so long as you're willing to hold your Pixel steady.

Photo by Florian Kainz, via Google

The info comes courtesy of a caption attached to a promotional gallery of Night Sight snapshots put together by Google.

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Pixel Night Sight also works in daylight, reducing noise and boosting resolution was written by the awesome team at Android Police.

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‘An Unshakable Humanism’ — Michael Chabon on Stan Lee

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Michael Chabon, on Instagram:

Some people are influences. Others — a rare few — rearrange the very structure of your neurons. Stan Lee’s creative and artistic contribution to the Marvel pantheon has been debated endlessly, but one has only to look at Jack Kirby’s solo work to see what Stan brought to the partnership: an unshakable humanism, a faith in our human capacity for altruism and self-sacrifice and in the eventual triumph of the rational over the irrational, of love over hate, that was a perfect counterbalance to Kirby’s dark, hard-earned quasi-nihilism. In the heyday of their partnership, it was Stan’s vision that predominated and that continues to shape my way of seeing the world, and of telling stories about that world, to this day.

There’s something apt about Chabon using a primarily visual medium like Instagram as an outlet for the perfect words to remember a man whose life’s work was writing for comic books.

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