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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!

There is a noticeable "shock wave" forms above the cumulus cloud as it rises in this video at 13 seconds in. Also a few more "shock waves" later on in the video too. Can anyone explain to me what is happening? I find it helpful to go to settings on the right and play it at 1/4 speed. What causes the "shock waves". Are they ice or water droplets? Why so sudden? Etc. Thanks Brian. I would love to hear the attempts to explain it. I view clouds as rising air that loses its water vapor as it condenses into water droplets. I also feel that the energy released as water condenses is driving some of the cloud (and air movement). Thanks Brian

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An article published in the journal "American Museum Novitates" - you can read it at - describes a research that provides the strongest evidence yet that sharks descended from a very ancient group of fish called acanthodians. A team of researchers led by John Maisey of American Museum of Natural History’s Division of Paleontology analyzed fossil remains that were exceptionally preserved of an ancient shark-lie fish called Doliodus problematicus identifying it as a transitional species between acanthodians and sharks.

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Liquid Biopsies

The progressive changes in or on the DNA of our cells, that lead to cancerous tumours or leukaemia, can increasingly be detected simply with a blood test, despite the minute and fragmented nature of the cellular debris that is found there, thanks to continuing improvements in technology. Such cancers can more readily be detected, treatment monitored and resistance mutations identified, with significantly less discomfort and anxiety for the patients, especially when compared with the deep needle scraping of bone needed for today's bone marrow biopsies, thanks to new Liquid Biopsies being developed by a husband and wife team of Australian scientists Drs. Sarah-Jane and Mark Dawson and others.

Mark Dawson: So the two major cancers that we've studied here are a disease called chronic lymphocytic leukaemia, and another precursor condition called myelodysplastic syndrome. So if we start with the latter, the latter is really a problem of the production factory for our blood cells, which is the bone marrow. And so…

Norman Swan: And you really teeter on a knife-edge of leukaemia when you've got MDS.

Mark Dawson: Correct, that's exactly right, Norman. And really here the quality and quantity of the cells that are being produced is not adequate. But this is actually a relatively common disease that is quite difficult to diagnose, because there are a number of different everyday exposures that may give rise to low blood counts: infections, some of the toxins that we consume such as alcohol, and other toxic exposures as well. So it's not always clear whether the low blood counts are caused by a cancer. But all cancers, as you've just been talking about, have a somatic or acquired mutation in their DNA. And essentially that's what we look for, we look for an abnormality that says that the cells are cancerous. We do that currently with a bone marrow biopsy, but what our results suggest is that we may be able to do that effectively with the liquid biopsy.

More and listen here (stream, download, podcast, or this transcript):

"Through advances in technology we now have better tools to be able to measure really small and tiny fragments of DNA in the blood and we can start to use that information to get some understanding about how patients are responding to therapy," said Associate Professor Sarah-Jane Dawson."

More here (article):

Blood tests that fish for either tumour DNA or cancer cells in patient blood samples are showing great promise. This type of blood analysis is helping Cancer Research UK scientists and doctors better understand the biology of cancer from its earliest origins to when it spreads around the body. And it has the potential to offer a new way of monitoring how patients respond to treatment, as well as how drug resistant tumours may begin to emerge.

More here (YT ~2mins.):

This somehow reminds me of a recent post by +Irina T. :
A Splash of River Water Now Reveals the DNA of All Its Creatures

Image supplied by Kirrily Payne from the second link.
Lexi Davies, 2, has leukaemia


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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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Humpback whales demonstrate sophisticated division of labor and timing to blow bubble nets to capture herring. These sophisticated behaviors are a kind of social intelligence. Could these whales have also developed a sense of empathy?

Humpback calves are vulnerable to attacks by orca whales. And humpbacks will travel for miles to defend a calf under orca attack.

But humpbacks will also defend other species when they are attacked by orcas.
The humpback whales could be instinctively responding to a orca attack and saving another animal an unintended side effect. But other aspects of their defense make this seem unlikely.

They do this even at great expense to themselves not feeding or even resting for as long as seven hours. They physically block the orcas using their fins to bat the other whales.

It could be that the humpbacks are getting revenge on the orcas for their attacks on calves or trying to intimidate and frighten them.
But look at the first video clip below of a humpback carrying a seal on it's flipper to protect it from a orca. The whale is swimming on it's back something that would seem as hard as running backwards. It stays on the surface because if it submerges the seal will be swept off and attacked by the orca following behind. Could the humpback also be aware of the seals need to be above water to breathe? In any case it seems to me that the humpback is actively protecting the seal and doesn't want to see it harmed.
That is empathy to me.

Humpback carrying a seal on its flipper to save it from an orca (original source unknown);
From Planet Earth live Humpbacks try to rescue a grey whale calf from Orcas;

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Neanderthal variants present in the genome of human allele provided evolutionary advantages such as increased immunity and uncommon skin pigmentation attributes.New studies in the domain have identified 126 different places in the human genome where genes inherited from archaic humans remain at unusually high frequency in the genome of modern humans
So evolution ha?
Someone please take a look at this.

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For anyone interested in Heart Disease and encouraging people to look at taking a bio-psycho-social approach. This is the new lengthy (has time stamps) basic video for the general public. (3rd in a series of 5 that will be available for CEU credits soon for all healthcare providers)
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