After reading Rajini Rao’s champagne science post, I figured I should join in. Except most of you know I drink beer and not much wine or champagne. Also, since the champagne post is related to New Years celebration, I’ll mention that craft beer in the USA, in the Midwest in particular, is improving every year. Here’s to more craft beer in the Midwest.
Rajini’s post reminded me of two beer-bubble related posts. One is why do bubbles sink when you pour a glass of Guinness stout. The other is what causes a “beer volcano”.
Part I: Sinking Bubbles
Guinness stout and a few other beers, e.g., Boddingtons Pub Ale, have nitrogen gas in them, in addition to carbon dioxide. It creates a creamy head and takes away some of the bitterness (from the hops) that some people don’t like. Some of you may know that Guinness and Boddingtons in cans, have a widget, which is a plastic device with pressurized nitrogen. It helps recreate the pub experience of a draught beer. Did I mention rabbit holes? Back to sinking bubbles. Physicists at the University of Limerick in Ireland published a beautiful paper based on simulations and experiments, explaining why bubbles sink instead of rise in a pint of Guinness.
Fluid Dynamics
Benilov et al, explain that the small (nitrogen and carbon dioxide) bubbles sink along the surface of the glass while the bubbles in the center of the glass rise. Using the Bond number, Stokes formula, Reynolds number, and void fraction, they simulated bubbly flow for various shapes of glasses. The Bond number helps determine the shape of the gas bubbles. The Stokes formula is used to estimate velocity. The Reynolds number is used to determine whether you have laminar or turbulent flow and the void fraction estimates the amount of volume that the gas contributes to. It turns out that the shape of the glass matters. If the glass has a wide opening that narrows towards the bottom, the bubbles will sink. If the opening is smaller at the top, like a beer bottle, the bubbles won’t sink.
All of this lead me down memory lane (which seems fitting at the end of the year) as Reynolds numbers and Stokes equations factored heavily in my undergrad studies as a chemical engineer. Again, speaking of rabbit holes, I was fascinated to find that the Navier-Stokes equations are part of the Clay Mathematics Institute seven most important open problems. From the Wiki: The Navier–Stokes equations are also of great interest in a purely mathematical sense. Somewhat surprisingly, given their wide range of practical uses, it has not yet been proven that in three dimensions solutions always exist (existence), or that if they do exist, then they do not contain any singularity (they are smooth). These are called the Navier–Stokes existence and smoothness problems.
Part II: Beer Volcano
Some of you may know the prank where you smack your mate’s open beer bottle with a strong hit and the beer comes gushing out. Now with good craft beer, that would be sacrilegious so I won’t be surprised if my beer pals are not aware of such shenanigans. Again, fluid dynamics tells us that it is due to a mushroom cloud, not unlike that of an atomic bomb.
Rodriguez-Rodriguez et al explain that a compression wave is generated by the sudden vertical impact on the beer bottle and that waves bounce back and forth until damped out. The free surface at the small bottle opening is key to forming the train of expansion/compression waves that drive the bubble implosions. The rapid collapse of the bubbles is called cavitation, which is a serious problem with pump failures.
I better wrap up this post before I go down another rabbit hole. So cheers and a happy New Year to you.
These twelve items have two important things in common:
(1) They’re important and valuable things, and
(2) They have absolutely nothing to do with autism.
Lead is a heavy metal which melts at low temperatures. It’s used in large batteries like the ones in your car, as well as as a stabilization weight and radiation shield. It can be poisonous if you ingest it, though, so be careful! (The #1 safety risks in most radiation labs is actually accidental lead poisoning from the shielding equipment)
Fluoride is an ion of the Fluorine molecule. It’s critical for human health: without it, your teeth will decay and fall out. In some places, it’s found naturally in local foods and water, but in other places, it gets added to reservoirs or table salt instead. Water fluoridation is considered one of the ten greatest public health achievements of the 20th century, and is a major reason why people today have healthy teeth. It was also believed by some to be part of a Communist plot to corrupt the Purity of Essence of our Precious Bodily Fluids. (And yes, people describing the plot Liked to Capitalize Things)
Antibiotics are probably the single greatest public health improvement of the twentieth century: they’re drugs which can give our immune system the capability to fight off bacterial infections. Without them, common diseases like strep and TB will simply kill you. However, antibiotics do nothing against viruses. In fact, if you don’t have a bacterial disease, or take only part of a course, antibiotics are dangerous: they’ll kill just the bacteria which were most vulnerable to them, leaving behind the strongest and most resistant ones to breed! Overuse of antibiotics has resulted in the development of many strains of bacteria which are resistant to even very powerful antibiotics, leading to the fear that we may soon be vulnerable to these diseases again. The most important things you can do are (a) don’t ever pressure a doctor to prescribe them when they aren’t appropriate, and (b) fight their overuse in ranching, where they’re given as prophylactics to otherwise healthy animals — thus breeding deadly resistances.
Vaccines are antibiotics’ competitor for greatest public health victories. They’re small doses of dead or weakened viruses which are injected into you, letting your immune system learn to recognize and destroy the real ones when they come. They’re the reason that so many of the deadliest diseases of the past — smallpox, measles, pertussis, and the like — are things of the past. However, unscrupulous folks have tried at times to convince the public that these are dangerous (generally as part of a scheme involving lawsuits), and as a result, some people are avoiding them! This can cause many other people to die, because of what’s called herd immunity. You can learn more about vaccines from this great comic:
Pesticides are chemicals which kill pests which destroy crops. These are a dangerous, but important, tradeoff: their residues can be poisonous, especially if they accumulate in groundwater; they can kill insects which are not just beneficial, but critical, like bees; and their misuse can lead to monoculture, which we’ll talk about in a moment. On the upside, they greatly increase crop production, and have been a major factor in ending starvation. They can also kill insects like the tsetse fly and malaria mosquito which are major vectors of disease. Together, this makes them a powerful lifesaving tool which has to be carefully managed.
GMOs are any sorts of organisms whose genes have been modified. This is a blanket term for a wide range of things, from corn that produces additional nutrients, to wheat that can grow in a wide range of climates, to goats which can produce antibiotics in their milk (!), to crops which are immune to certain pesticides and herbicides. “GMO” is a term for the technique which produces all of these. Some of these are huge benefits, but some of them are dangerous: for example, herbicide-resistant crops can be doused with huge doses of powerful weed-killers. In addition to their normal risks, this creates what’s called a “monoculture,” where only one species of plant can survive. This can make an entire crop vulnerable to a single blight, so it’s extremely dangerous for food security. Also, many companies who make such products are known for unethical business practices, so many people hear “GMO” and think of them. But don’t be led astray! GM is a technique which saves lives, too.
Balloons may make you think of things at birthday parties, but they’re also the best way to get high into the stratosphere. Weather balloons, made of modern materials like mylar and kevlar and filled with Helium, can fly over 100,000’ above the ground fairly cheaply, making it possible to understand weather patterns in places where satellites can’t be. They were also the way the recent record-breaking skydivers got up: you can watch Alan Eustace’s record-breaking jump at https://www.youtube.com/watch?v=AsftfzBrVko. In the process of doing this, he and his team invented several new technologies which should make flight safer, balloons cheaper, and more.
Tubesocks are long socks which can protect your shins. More important than protection, they wick moisture away from your feet, which are some of the heaviest sweat-producers in your body: they can produce as much as a quarter-pint of sweat each day. By moving the moisture away, they can protect you from frostbite in the cold, and fungi like athlete’s foot in the heat.
Testicles are the organs in which sperm is produced in male animals. They’re also important glands, producing hormones such as testosterone which help regulate bodily function. They hang outside the body in most land mammals in a sac called the scrotum, because sperm production works best when the testes are kept below body temperature. Because your body considers them pretty important, they’re therefore covered with nerves to quickly tell if something’s wrong. That means that you don’t want to hit them, but that they often enjoy gentle touch.
Bunnies, also known as rabbits, are small mammals with big ears. They’re shy herbivores, depending for their survival upon their ability to hear and quickly run away from prey – but also on their ability to reproduce quickly, so that their groups can sustain losses and keep going. Most species of rabbit live in burrows, often networked together to form a warren. People’s opinions of them are split: some people raise them for food or fur, while others love them as pets. They can also turn into a plague, as happened when they were introduced into Australia: feral rabbits caused tremendous damage to agriculture and local species. You can see many pictures of bunnies at http://goo.gl/FVlVJD.
Strippers are a kind of sex worker. Most famously, they perform erotic dances (often using a fixed pole as a prop) for an audience. But most of their work takes the form of one-on-one interaction with patrons, performing individually for them in settings from the public (such as table dances) to private rooms. Strippers will create one or more personas for this, working to create a fantasy environment for the patron in which they feel aroused, appreciated, and at the center of attention. Many strippers travel from city to city around the year, as the best business is often found in different places at different times. The most important thing to remember about strippers is that, while they may be playing any number of roles that seem different, they are professional entertainers and should be treated with respect.
Dromedaries are the famous “one-humped camels” of the Sahara and Arabian deserts. Their two-humped Bactrian cousins live further east. Dromedaries are known for their incredible ability to store water in their bodies, allowing them to travel across the entire desert. Unlike horses, they have paws rather than hooves, which gives them excellent traction on difficult terrain. As a result, they are highly valued as pack and riding animals, and camel racing is a major sport. Dromedaries were what made the Spice Road and the western part of the Silk Road possible, and they continue to be an important way to transport people and goods across the desert to this day.
So next time someone shows you a list like this, think through all of the various items in them and realize all of the ways in which they’ve made our world a better place. Some of them, like pesticides and bunnies, involve tradeoffs which you need to manage carefully; others, like antibiotics and vaccines, simply need to be used correctly to make the world a better place.
This octopus smashed the record for egg brooding. She spent 4.5 years protecting her eggs in Monterey Bay. You can read more about her here: http://goo.gl/AIBCzN
So of the choices at Science, this is my selection for image of the year, 2014. What’s your? http://goo.gl/oRmJwM
I really enjoy Compound Interest’s post and this one follows my Christkindlmarket post nicely. Glühwein anyone? Make sure you click on the link and not just the infographic or you’ll miss these gems:
Eugenol also has a mild anaesthetic effect, which is one of the reasons that clove oil is occasionally used as a traditional remedy for toothache.
Myristicin actually lends nutmeg hallucinogenic qualities, but only in doses larger than those commonly used in cooking and mulled wine making. Allegedly, the effects of ingesting the nutmeg required are none-too-pleasant, so it isn’t an experience that comes recommended!
Cinnamaldehyde, which makes up around 90% of the essential oil of cinnamon bark, is the main contributor to this flavour, and to the aroma of cinnamon. It has also previously been added to chewing gums, and research has shown it to have some antimicrobial effects.
#ScienceEveryday
Originally shared by Compound Interest
Not much beats a mug of mulled wine on a cold winter’s evening. Here’s a breakdown of some selected chemical ingredients: http://wp.me/p4aPLT-QJ
In the infographic below, they bust the myth about chloroform being used for nefarious activity. Chloroform takes about 5 minutes to have an effect. That’s not what’s portrayed in the movies.
Maybe Compound Chemistry will inspire posts by our resident chemist, Siromi Samarasinghe.
Clearly #Sacks4Science needs to be a thing to support testicular cancer research and fight sexism in science. Since I don’t have a post about testicular cancer, I’m re-sharing this post about prostate cancer. Let me explain where the #Sacks4Science hashtag is coming from.
There’s a post about a group in Italy that want to promote science by showing pictures of breasts with a sign about science.
That is almost as bad as the #HUGS4JUGS “campaign”. The only time that breasts should be mentioned in a conversation about science, is if the science is about breasts.
Some pedantic arguing ensued on that thread, so I turned my attention back to science. I’m working on data to see if a new imaging agent can detect if a tissue is positive for the progesterone receptor, which would guide therapy choices without invasive biopsies.
In a conversation about the boobs for science post, Rachel Blum said
Clearly: ask for guys to do a shot of their penis untying at an important section in a scientific paper. Share a few shopped ones with the MOAR BOOBS crowd.
“Oh, that makes you uncomfortable? But it’s FOR SCIENCE”.
I mention it should be for prostate cancer awareness or show your balls for testicular cancer awareness. I bet a lot of bros will jump on that bandwagon.
Then Buddhini Samarasinghe said, we should call the campaign “Sacks for Science”. We all agreed that #Sacks4Science needs to be a thing. So support #Movember and prostate cancer awareness. Support science, without sensationalizing it. And if you’re ready to jump on the bandwagon, help us support #Sacks4Science to support testicular cancer research and fight sexism in STEM.
#ScienceEveryday
Originally shared by Chad Haney
The real #Movember for #ScienceSunday .
Most of you probably know that the pink ribbon in October means, breast cancer awareness month. I disagree with the commercialization of the pink ribbon and attempts to trademark it, but that’s another story. I want to talk about Movember. You’ve seen the mustaches and the hashtag. How many of you know it is for men’s health awareness? Specifically prostate and testicular cancer. I’m going to focus on prostate cancer.
PSA about PSA
Public service announcement about prostate-specific antigen screening: For many years, PSA testing was suggested to start at age 40. The current recommendation:
The American Cancer Society recommends that men discuss the possible risks and benefits of prostate cancer screening with their doctor before deciding whether to be screened. The discussion about screening should take place starting at age 50 for men who are at average risk of prostate cancer and expect to live at least 10 more years. It should take place at age 45 for men who are at higher risk, including African-American men and men who have a father or brother diagnosed with prostate cancer, and at age 40 for men at even higher risk.
For many years researchers in the trenches were finding that PSA screening often led to false positives. There’s too much variability in the PSA screening method.
Ex vivo MRI
The purpose of the study that I’m presenting was to take advantage of higher resolution MRI, using ex vivo samples in a pre-clinical high field MRI scanner (9.4T vs. 1.5T clinical MRI). Histology is orders of magnitude higher resolution even compared to the pre-clinical scanner. The idea was that better MRI images could be correlated with histology. Ultimately decisions are made based on histology, typically via biopsy. Identifying which features in MRI correlate with histology could set up a feed back loop to improve the in vivo MRI images. What’s shown below is an early proof of concept study.
I don’t know the PSA scores for the patients in the study below, but I’m sure they were high enough to justify biopsies. We were blinded to patient names and a lot of their health records for both privacy reasons and to remove bias. There are risks and side effects associated with getting a prostate biopsy. That’s part of the reason for changing the PSA screening recommendations. If you are curious what a human prostate looks like, there’s one pictured below. It’s about the size of the palm of your hand (at least my hand).
The other two figures show what the prostate looks like using MRI (panel A, C, and D) and histology (panel B). Panel A is a T2-weighted spin echo image. Panel C is a T2 map, i.e. a display of the actual T2 values. Panel D is an apparent diffusion coefficient (ADC) map. You can review the MRI terminology in the link below.
The first figure, which outlines the cancer with a dotted line in the histology image is from a 71-year-old patient. The second is from a 63-year-old patient without malignant cancer. In the examples below it isn’t obvious which MRI parameter best correlates with cancer. In the 71-year-old patient, the low T2 values along with low ADC values appears to correlate well with the tumor outlined in the histology slide. However, the 63-year-old patient also displays low ADC values, whereas the T2 values are higher. Overall, with 9 patients, the T2 values were about 10 msec longer (P < 0.03) and the average ADC values were about 1.4 times larger (P < 0.002) when comparing normal peripheral zones vs. cancerous peripheral zones. With a larger sample size we hope to improve the correlation between both the in vivo and ex vivo MRI with histology.
References:
Medical Imaging 101 pt 3: MRI from my #CHMedicalImagingSeries
Science Friday host Ira Flatow joins Sound Opinions hosts Jim DeRogatis and Greg Kot to discuss music and science. Then Jim and Greg dissect The Wall by Pink Floyd. The Wall (album) was released on 30 November 1979 almost 35 years ago. The movie followed in 1982. I have to agree with Jim and Greg’s statement that Waters had the creative genius that Gilmour lacked and Waters was nothing without Gilmour’s unique musical talent. In other words, they needed each other and Pink Floyd wasn’t as good after the split. They also discuss Wright and Mason’s contributions, just so you don’t think it’s all Waters and Gilmour. So have a listen. You might want to download the podcast.
References:
Your Brain on Jazz
Dr. Charles Limb from Johns Hopkins University discusses how jazz improvisation is like wordless communication, i.e., it uses the part of the brain for language. (see the PLoS One link within).
Ira Flatow mentioned a study where twins were used to determine how much practice plays a role in learning to play an instrument vs. the genetic influence.
I missed posting for Ada Lovelace Day this year. A lot of G+ friends have recently shared posts about gender bias in science and I decided to list them here along with my re-share of my Alice Kober post.
Ada Lovelace, was an English mathematician and writer chiefly known for her work on Charles Babbage’s early mechanical general-purpose computer, the Analytical Engine. Her notes on the engine include what is recognised as the first algorithm intended to be processed by a machine. Because of this, she is often described as the world’s first computer programmer.
Ada Lovelace Day is about sharing stories of women — whether engineers, scientists, technologists or mathematicians — who have inspired you to become who you are today. The aim is to create new role models for girls and women in these male-dominated fields by raising the profile of other women in STEM.
Deeksha Tare ‘s post about inventions by women (http://goo.gl/TLl3Z4) reminded me of a segment on The World on NPR. It was yet another story of an important breakthrough by a woman being overlooked. Alice Kober did a lot of the major analysis in deciphering Linear B but Michael Ventris received much of the credit, at least initially. Part of the lack of credit could be due to the fact that she worked on Linear B in private, i.e., in her “spare time”. She unfortunately died at the age of 43.
Linear B
So what is linear B? Linear B is a syllabic script from Knossos, Crete around 1450 BC. You can think of it as unlocking hieroglyps, without the Rosetta Stone. British archeologist, Arthur Evans found a series of clay tablets in ruins thought to be the home of King Minos. Linear B descended from Linear A which is an undeciphered earlier script for writing the Minoan language. Linear B consists of approximately 87 syllabic signs and over 100 ideographic signs.
Linear B had been known for about 30 years before Alice Kober began working on deciphering it. That’s 30 years with no breakthroughs. One of Alice’s breakthroughs was understanding that Linear B is syllabic, like Japanese where characters stand for a sound. The other two types of written language systems are alphabet, which we know, and logographic, like Chinese where a symbol represents a whole word. Part of the reason Linear B was not identified as syllabic earlier on is due to a few pictographs (like Chinese) that represented objects, e.g. horeses and pots.
Database
Instead of trying to guess meaning or speculate on sound values of symbols, Alice recorded the frequency of every symbol, in general and then in a particular position, which lead to the idea of Linear B being syllabic and an inflected language (having suffixes and prefixes). Keep in mind this was in the 40s and 50s with no computer aid. She handmade index cards for her database because of the limited supplies during WWII. From the database, Alice was able to build a grid showing the relationships between symbols but died before she could add sound.
It’s all Greek to me
Michael Ventris was able to add sound to the grid as he guessed that some repeated symbols might be towns in Crete. So Knosso in Linear B was “ko-no-so”. With a few city names figured out, he could add sound to the grid. No one had guessed that Linear B was a form of Greek because they didn’t know Greek was spoken that far back. Since Greek using the alphabet system, it wouldn’t have helped much, knowing that Linear B was a form of Greek. So the end story is that the Greeks colonized Crete and used the local writing system to record their own language.
Sources:
How American Linguist Alice Kober Helped Unlock the Secrets of Linear B
If you didn’t guess I vote no, then you don’t know me. Even if a politician has a science background, they should not interfere with peer review.
#ScienceSunday
Originally shared by ScienceSunday
Should politicians be involved with reviewing research proposals?
Bill McGarvey is very familiar with the grant proposal review process for the National Institutes of Health in the USA. The NIH funds the majority of biomedical research in the US. Bill shares an interesting article discussing politicians getting involved in the review process for the National Science Foundation, who fund a lot of basic science research in the US. Because basic science research has minimal immediate impact but often a huge impact long term, it frequently comes under scrutiny by short sighted politicians.
Politics and the National Science Foundation (NSF)
Snow leopards have declined in population by 20 percent over the past two decades—primarily due to human activity—but in one community, the cat lives on.
