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Important to do back-of-the-envelope math. How can you tell if it holds a certain liquid otherwise?
Ask not how many engineers does it take to change a light bulb. Ask how many men does it take to pee in a swim pool. Answer: 375 in three weeks by my calculation, if the recent Canadian study is to be trusted. (And you can have +James Wilson to thank:-)

Before your collective "ew", however, consider some back-of-the-envelope math. To start: 20 gallon of urine in 22,000-gallon pool represents <10ppm of added impurities, impossible to cause eye irritation and other discomfort that a healthy person's pee could cause.

Then, thanks to the poor job Huffington Post does to relate nuances in the paper, I am able to claim a plausible extrapolation between a WHO report, Wikipedia and various citations from medical literature: One man's urination is eight men's perspiration when it comes to excess ACE level that Lindsay Blackstock uses to declare detection of urine. If this extrapolation holds any water - not urine, it would take only 15 swimmers sweating each hour the pool is open to make up the same ACE level.

Finally, a word of the wise to men - or should I say, pigs? If you desire to pee in a public pool but do not wish to be caught, drink not diet cola. Man up and drink pool water instead!

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Bee Microbiome Disturbed

It seems that, like us and other mammals, but apparently unlike many other insects, bees, have a socially-acquired gut microbiome with a variety of bacteria in a kind of ecological equilibrium. Treating bees with the broad-spectrum antibiotic, Tetracycline, disturbs this balance and appears to lead to shorter lives for treated bees, possibly in-part by letting less helpful bacteria get a hold.

To conduct the study, researchers removed hundreds of bees from long-established hives on the rooftop of a university building and brought them into a lab where some were fed a sweet syrup with antibiotics and some were fed syrup only. The researchers painted small colored dots on the bees’ backs to indicate which had received antibiotics and which had not. After five days of daily treatment, the bees were returned to their hives. In subsequent days, the researchers collected the treated and untreated bees to count how many were still living and to sample their gut microbes.

About two-thirds of the untreated bees were still present three days after reintroduction to the hive, while only about a third of the antibiotic-treated bees were still present.

More here (University of Texas PR):

UT Austin postdoctoral researcher Kasie Raymann loves bees. In fact, she handles thousands of bees each month in her research on antibiotics and the possible effects they have on the gut microbes of these tiny insects. Watch her at work in the lab and learn more in this short video.

Video (YT ~1min.):

There is growing evidence for the importance of gut microbes in animal health. Unlike most other insects, honeybees possess a highly conserved gut microbial community, which is acquired through social contact, and several results have suggested that these microbes play an important role in honeybee health. Antibiotics, which can severely disrupt gut microbial communities, are commonly used in beekeeping in several countries. However, it is unknown how antibiotic treatment affects the gut microbial communities of honeybees. Here, we evaluated the effects of antibiotic treatment on the size and composition of the honeybee gut microbiome and on honeybee health. We found that exposure to antibiotics significantly alters the honeybee gut microbial community structure and leads to decreased survivorship of honeybees in the hive, likely due to increased susceptibility to infection by opportunistic pathogens.

Paper (open):

Image from Press Release above.

Annoyingly this post could equally well fit in my Bees collection or perhaps my Antibiotic Resistance collection.


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Martian Flyby Simulated

Using the static, high-resolution, but greyscale images provided by NASA's HiRise Mars-orbiting camera, Finnish filmmaker and self-confessed Space enthusiast, Jan Fröjdman, has gone to the trouble of manually selecting and interpolating more than 33,000 reference points between images, and then rendering a coloured, dynamic, 3D simulation of the view one might get if, rather being in orbit, we were to be in futuristic spacecraft with a viewing portal, flying over the surface of Mars.

To fully appreciate the Martian landscape, one needs dimension and movement. In the video you see here, Finnish filmmaker Jan Fröjdman transformed HiRISE imagery into a dynamic, three-dimensional, overhead view of the Red Planet—no glasses required.

For Fröjdman, creating the flyover effect was like assembling a puzzle. He began by colorizing the photographs (HiRISE captures images in grayscale). He then identified distinctive features in each of the anaglyphs—craters, canyons, mountains–and matched them between image pairs. To create the panning 3-D effect, he stitched the images together along his reference points and rendered them as frames in a video. “It was a very slow process,” he says.

More here (article):

The anaglyph images of Mars taken by the HiRISE camera holds information about the topography of Mars surface. There are hundreds of high-resolution images of this type. This gives the opportunity to create different studies in 3D. In this film I have chosen some locations and processed the images into panning video clips. There is a feeling that you are flying above Mars looking down watching interesting locations on the planet. And there are really great places on Mars! I would love to see images taken by a landscape photographer on Mars, especially from the polar regions. But I'm afraid I won't see that kind of images during my lifetime.

More text and video (Vimeo ~ 5mins.):
Please watch the film in 2K if possible for greater details.

Jan Fröjdman (blog post):


Image from article.
Originally HiRise NASA/JPL/University of Arizona
Animated Photo

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Animated Textbook Linear Algebra
via u/filosoful

Like something from the fictional Daily Prophet newspaper, this Linear Algebra textbook under development by J. Ström, K. Åström, and T. Akenine-Möller contains animated figures.

After using linear algebra for 20 years times three persons, we were ready to write a linear algebra book that we think will make it substantially easier to learn and to teach linear algebra. In addition, the technology of mobile devices and web browsers have improved beyond a certain threshold, so that this book could be put together in a very novel and innovative way (we think). The idea is to start each chapter with an intuitive concrete example that practically shows how the math works using interactive illustrations. After that, the more formal math is introduced, and the concepts are generalized and sometimes made more abstract. We believe it is easier to understand the entire topic of linear algebra with a simple and concrete example cemented into the reader's mind in the beginning of each chapter.

More here (online textbook):
by J. Ström, K. Åström, and T. Akenine-Möller

Related post:
Topology by u/3Blue1Brown


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Edit: Here's the paper if anyone wants a level of detail.
Our new observations of AFGL 3068 taken with the Atacama Large Millimeter/submillimeter Array (ALMA; see Methods for details on observations and data calibrations) unveil exceptionally detailed features in its CSE (Fig. 1; individual molecular lines are presented in Supplementary Figs 1–3). A spiral pattern is definitively detected over a radius of 10ʺ, corresponding to 10,000 au at the distance of AFGL 3068 (~3,400 ly) in the 12CO J = 2−1 and 13CO J = 2−1 molecular lines (see middle panel of Fig. 1; J is the rotational quantum number). The HC3N J = 24−23 line best highlights the innermost winding of the spiral pattern. The emission maps integrated over the molecular lines are well correlated with the HST image, thus verifying that the circumstellar dust and molecular gas trace the same spiral feature. Remarkably, the molecular line maps reveal the presence of the innermost winding of the spiral (r < 3ʺ), which was absent in the dust-scattered light image.

More here (Nature Letter (open)):
Big Ellipse

When the Hubble Space Telescope first took a now famous picture of an old star surrounded by a gigantic spiral of gas, about ten years ago, it was the first time that such a phenomenon had been reported. Now, the ground-based system ALMA, in the Atacama Desert of Chile, has taken a peer at and through the three-dimensional cloud around the giant and aging star LL Pegasi and allowed Hyosun Kim from the Academia Sinica Institute of Astronomy and Astrophysics, Taiwan and other international astronomers, to build a conforming model that predicts the shape of the elliptical orbit of LL Pegasi and its carbon star binary partner, despite the fact the orbital period is measured in hundreds of years.

The new ALMA images reveal the detailed features of spiral-shell pattern imprinted in the gas material continuously ejected from LL Pegasi. A comparison of this observation with computer simulations led the team, for the first time, to the conclusion that a binary system with a highly elliptical orbit is responsible for its morphology of gas distribution. In particular, the bifurcation of the spiral-shell pattern, which is clearly visible in the ALMA images, is a unique characteristic of elliptical binaries. This quintessential object opens a new window on the nature of central binaries through the repetitive patterns that reside far from the star at distances of a few thousand the stellar radii.

More here (ALMA PR):

“What we are seeing in splendid detail with these observations is the final act of a dying red giant star, as it sheds most of its gaseous bulk in a strong, outflowing wind,” said study co-author Mark Morris, UCLA professor of physics and astronomy.

After comparing their telescopic observations with computer simulations, the astronomers concluded that a highly elliptical orbit is responsible for the shape of the gaseous emissions surrounding this system.

More here (UCLA PR):

Image from first link.
Animated Photo

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Different Fields

Under the auspices of the French National Centre for Scientific Research (CNRS) and their National Institute for Mathematical Sciences (INSMI) in particular, Christoph Sorger its director, interviews two Mathematicians notable for their early promise and French connections: Cédric Villani, Fields Medalist 2010, and Artur Ávila, Fields Medalist 2014.

Christoph Sorger: Artur, you received the medal more recently, in August 2014 in Seoul. Tell us about your experience.
Artur Ávila: Immediately after the event, there was obviously a bit of pressure to talk about it, especially in the media. There seems to be much greater interest in mathematics in France than in other countries. It’s odd that the French value a prize like this one so much—I don’t know why it’s different elsewhere. I am particularly keen to make the most of this opportunity to promote mathematics in my native country of Brazil: things are on the right track there for the moment, but no one knows what the future holds. The next International Congress of Mathematicians (ICM) will be held in Rio de Janeiro in 2018. I see it as a kind of duty for me to be on hand, doing whatever I can since I’m not especially good at that kind of thing, and to help boost the image of mathematics in the collective imagination.

More here (interview):

The Fields Medal is a prize awarded to two, three, or four mathematicians under 40 years of age at the International Congress of the International Mathematical Union (IMU), a meeting that takes place every four years. The Fields Medal is sometimes viewed as the highest honour a mathematician can receive. The Fields Medal and the Abel Prize have often been described as the mathematician's "Nobel Prize". The Fields Medal differs from the Abel in view of the age restriction mentioned above.

The prize comes with a monetary award, which since 2006 has been C$15,000 (in Canadian dollars). The colloquial name is in honour of Canadian mathematician John Charles Fields.[5] Fields was instrumental in establishing the award, designing the medal itself, and funding the monetary component.

Fields Medal (Wikip):



Image from first link.

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Considering that NASA have recently uncovered one of their major discoveries to have ever been made so far, what are the other details that we have to know about our so-called ‘sister solar system’? How habitable are these seven newly discovered planets? Here’s what authorities have to say
#NASA #Trappist1

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Like something from Science Fiction, a Pyrosome, which lives in the warm upper layers of the ocean, is a brightly-lit tunicate colony of individual animals or zooids, each of which is only millimetres in length. The zooids are held together by a shared gelatinous tunic that starts off looking like a small butterfly net, with a point at one end and an opening at the other, but that may grow to tens of metres in length. Some scientists speculate that the zooids may co-ordinate certain behaviours that translate into a colonial behaviour, by sensing the lights of their fellow clones.

The movement and feeding of the colony is a joint effort and the whole pyrosome is like a giant filtration system. Each zooid sucks in water from outside the colony and blows it out again the other side. This not only feeds them but creates a rudimentary jet engine to give them some control over where they drift to.

Shutting off this propulsion system allows the colony to sink out of harm’s way – they regularly dive down to 500-700 metres and have been collected from as far down as 3000 metres. But because they are made up of so many small zooids, coordinating their actions isn’t easy. Unpublished research from David Bennett then at Bangor University, UK, offers tentative evidence that this is where a pyrosome’s impressive light show comes in.

When a pyrosome is brushed by an external object, it lights up like a Christmas tree – in red or white depending on the species. The signal ripples through the individuals, and they respond by cutting off their engines. Just think of a second world war U-boat film. When the red lights start flashing, it’s time to dive.

More here:

Pyrosomes often exhibit waves of light passing back and forth through the colony, as each individual zooid detects light and then emits light in response. Each zooid contains a pair of light organs located near the outside surface of the tunic, which are packed with luminescent organelles that may be intracellular bioluminescent bacteria. The waves of bioluminescence that move within a colony are apparently not propagated through neurons, but by a photic process.[3] Flashing zooids not only stimulate other zooids within the colony to bioluminesce, but nearby colonies will also display bioluminescence in response. Colonies bioluminesce in response to mechanical stimulation (touch), as well as to light.

Pryrosome (Wikip):

A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata, which is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords. [...]

Tunicates (Wikip):

Pyrosomes and salps are pelagic (free-swimming) tunicates or sea squirts. All species are open ocean animals that rarely come close to shore, and all are colonial, although many salps can also be solitary.

Pyrosomes are colonies of tiny animals that form hollow tubes sealed at one end - the long tube species in the first part of the video is giant pyrosome, Pyrostremma spinosum - this one is only about 15m long but it can reach 30m in length! Pyrosomes get their name (Pyro = fire + soma = body) from their ability to emit light (bioluminescence) - colonies can glow or flash light at night, particularly if touched.

Salps have much larger individuals than pyrosomes, individuals pump water through themselves. Colonies are formed of chains of individuals. Salps can form very high densities under good conditions, and are an important oceanic food source for fish.[...]

Video (YT ~1 min):

expo 2390 NOAA


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Is psychiatric diagnosis purely a decision based on principles of science, or is it more of a decision with enormous ethical challenges? 

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Lut Desert Ecosystem

Somehow, despite temperatures being observed over 70℃ (158 ℉), in the heart of the huge so-called Emptiness or Lut Desert (Dasht-e Loot) in Southern Iran, an ecosystem of animals including desert foxes, reptiles and insects, but not many plants, survives. Researchers and guides from Iran, the US and Europe recently set-off in a convoy of SUVs with gear to find out if, perhaps, the web of food was seeded by the bodies of fallen birds that failed in their migration over the desert. They were in for a few surprises.

Insects, too, are critical to the Lut's food web. Many nibble on plants on the desert's periphery and are in turn eaten by spiders, reptiles, and foxes in the Lut's interior, supplementing the nutrients in the ill-fated birds, says expedition member Hossein Rajaei, curator of Lepidoptera—moths and butterflies—at the Stuttgart State Museum of Natural History in Germany. Yet some live in the heart of the desert. When Rajaei set up light traps at night, he was surprised to count large numbers of moth species. "What do they do there? What do they eat there?" he asks. How the fly larvae he found in a pool of hypersaline water survive is another enigma, he says. And so is the question of how the Lut's denizens stay hydrated.

The answer may lie just below the surface. Before the expedition began, AghaKouchak had scrutinized satellite sensor data from the Lut. To his surprise, microwaves emanating from the ground suggested that in some parts of the oven-hot desert, the soil is moist. Perplexed, AghaKouchak consulted a colleague, who proposed that the Lut's soil is so dry that microwaves were radiating from deeper layers of soil or even rocks, falsely indicating shallow moisture.

Last month, in the heart of the desert, the team's convoy entered "a flat landscape, as far as you can see," the hydrologist says. A short distance onto the plain, one of the trucks broke through several centimeters of hard, crusty soil and sank, up to its axles—in mud. After another SUV pulled out the stricken vehicle, "you could actually see water" where the tires had been. "It was hard to believe," AghaKouchak says, "but the area is really, really wet."

More here (article):

Measurements of MODIS (Moderate-Resolution Imaging Spectroradiometer) installed on NASA's Aqua satellite from 2003 to 2010 testify that the hottest land surface on Earth is located in Dasht-e Loot and land surface temperatures reach here 70.7 °C (159.3 °F), though the air temperature is cooler.[

Dasht-e Loot (Wikip):

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