It is frequently pointed out that the magnetic north pole lies slightly outside the geographic North Pole. This is not technically correct. In fact, the opposite is true. The Earth’s magnetic south pole lies just outside the geographic North Pole. In geography, North is defined by the direction that attracts the north end of a compass, but in physics, the north end of any magnet will always be pulled toward the southern direction of an external magnetic field. What this means is that the magnetic pole that lies in what we call the Northern Hemisphere is actually a magnetic south pole. In precise scientific terms, the “north magnetic pole” and the “magnetic north pole” are exact opposites. Thankfully, these needlessly confusing semantics are usually ignored in favor of the colloquial understanding.
Literature is full of descriptions of monstrous whirlpools like Charybdis, which threatens Homer’s Odysseus. While it’s not unusual to see a small free vortex in bodies of water, most people would chalk boat-swallowing maelstroms up to literary device. But it turns out that, while there may not be permanent Hollywood-style whirlpools, there are several places in the world where the local tides, currents, and topology combine to produce turbulence, dangerously vortical waters, and even standing vortices on a regular basis.
One example is the Corryvreckan, between the islands of Jura and Scarba off Scotland. In this narrow strait, Atlantic currents are funneled down a deep hole and then thrust upward by a pinnacle of rock that rises some 170 m to only 30 m below the surface. The swift waters and unusual topology produce strong turbulence near the surface and whirlpools pop up throughout the strait. Other “permanent” maelstroms, such as those in Norway and Japan, arise from tidal interactions with similar structures rising from the sea floor.
28 April 2013
Recoating Damaged Nerves
Nerve cells in our brains and bodies have long thin protrusions called axons, which transmit electrical signals both to other nerve cells and to body tissues. Wrapped around these axons are multiple thin layers of a substance called myelin, which not only protects the axons but also speeds up their signal transmission. Myelin is itself a type of cell called a Schwann cell and, if myelin becomes damaged by physical injury or disease – such as multiple sclerosis – the Schwann cells attempt to re-myelinate the axons. But the process is often insufficient and the damaged nerves might never fully regain their function. Researchers would thus like to enhance the natural re-myelination process to help damaged cells recapture their lost potential. A new technique that allows re-myelinating Schwann cells (stained green) to be distinguished from undamaged myelin (stained red) should help researchers understand the process and ultimately design treatments to improve it.
Written by Ruth Williams
We wondered what a derivative is. Imagine you have a graph with temperature on the y-axis and x on the x-axis. If you pick two points on the graph you can calculate the difference in their y values and the difference in their x values. Dividing those, you would get ΔT/Δx.
In the top-left graph we pick two points far apart. Going from the first point to the second we move 3.1 spaces down on the y-axis, so that ΔT is -3.1. We move 5.5 spaces on the x-axis so that Δx is 5.5. Doing the math it’s -0.56.
But look, if we pick different points we get different values. In the top-right we get -1.67, and in the bottom-left we get -0.36. It depends on what two points we pick.
Now this is a derivative: what if we say the two points we pick are zero distance apart so essentially they are the same point? That is dT/dx, shown in the bottom-right. Each point on the graph will have a different dT/dx value, which is the derivative at that point.
This is now calculus btw, because we talked about two points zero distance apart. (Or an “infinitesimal distance apart” which means infinitely close together.)
Needle playing a record | Victrola Coffee Roasters
Coloured scanning electron micrograph (SEM) of the needle (stylus) of a record player in a groove on a record. A record is used to store sound. It is produced by a machine with a head which vibrates in time to the sound being recorded. This cuts a groove in the record which varies according to the vibrations. A needle can then reproduce these vibrations as it runs along the groove and these, when amplified, produce the original sound.
The universally acknowledged Irish mascot that is the three-leafed clover is also known as trifolium repens, which hints at the rarity of the phenomenon of the very existence of a clover with four leaves. The first half of it’s scientific name, trifolium, in layman’s term means three-leafed. Statistically it’s estimated one out of about every 10,000 clovers is four-leafed.
This mis-interpreted symbol of luck is more of a genetic rarity than a bringer of good fortune. Scientists from the University of Georgia studied the DNA of the white clover in 2010, the same plant that is symbolically related with St. Patrick’s Day, and not only discovered previously-unknown genes, but revealed one of the newly-observed genes was the very genetic mutation that caused the phenomenon of the “lucky” four-leaf clover. The scientists also revealed the reason four-leaf clovers are rare is because the very gene that causes the growth of an extra leaf is, more times than not, closeted by a different gene that regulates the three-leafed trait. The published work of these scientists is available here in the journal Crop Science.
Even more surprising is that the genetic rarity of extra-leaf-growth doesn’t stop at four. There have been known instances of people finding five-leaf clovers, there’s even a Guinness world record for a clover with the most leaves, which just so happens to be 56, which was discovered by Shigeo Obara in Hanamaki City, Japan in 2009. Even better, Shigeo is a retired crop researcher, with a focus on breeding clovers, specifically, which means he had mutually impressive previous world records of abnormally leafed clovers. In 2008 he revealed his 21-leaf clover, which trumped his 18-leaf clover from 2002.
So next time you find a four-or-more-leaf clover, don’t thank luck, thank genetic mutations. While it is, and most likely forever will be, a symbol of good fortune, it is much more than that; due to it’s abundance, and a family grouping of over 300 species in the Trifolium family, it is not only a vital crop for many farmers the world over, but can even be used as livestock feed or compost matter, and the clovers respective flowers are one of the honeybees’ favourite main source for nectar.
Where does the saying “pee like a race horse” come from?
Exercise-induced pulmonary hemorrhage (EIPH) is a possible sequelae of very intense aerobic exercise. It is associated with the very extreme and dynamic changes in cardiac function, oxygen intake and vascular transit in the lungs that can cause stresses on the blood vessels leading to loss of integrity.
EIPH can be seen in human athletes but also in racing greyhounds, camels, and most commonly horses.
The results of EIPH are microscopic lung damage, coughing, swallowing of blood, and epistaxis - the bleeding from the nostrils - when it involves the upper respiratory tract. Together, they have a marked negative impact on performance.
Historically, one of the therapies that race horse jockeys used was furosemide, a diuretic. It would be given to horses before a race, increasing voids and reducing fluid volume and thus the vascular strain of EIPH and improving performances.
Because of the dramatic effects of furosemide and its visibility in popular cultural, the phrase “pee like a race horse” was born.
“Imagine a complex society that can accomplish amazing things, but also has an error in its programming that, occasionally, causes many of its members to run amok and die tragically. This is the situation faced by some species of ants, and the behavior is called a death spiral or an ant mill. You can see several examples in the videos below. The ants seem to have gone insane, walking in an endless circle together.
Beebe (1921) described a circular mill he witnessed in Guyana. It measured 1200 feet in circumference and had a 2.5 hour circuit time per ant. The mill persisted for two days, “with ever increasing numbers of dead bodies littering the route as exhaustion took its toll, but eventually a few workers straggled from the trail thus breaking the cycle, and the raid marched off into the forest.”
The cause of this behavior is the technology ant societies use for ground navigation. They follow pheromone trails on the ground laid down by other ants, or they simply follow other ants visually. The system works well normally. A scout ant goes out and finds something. Other ants go back to get more by following the scent trail, or by following each other. However, if a loop gets created, the ants will march blindly, sometimes circling until they die.
You can see an ant pheromone trail being formed in this video: Fire ant pheromone.”
Watch more videos of ant mills here.
Summer in the city can be especially hot and sticky, because urban heat islands exacerbate the warm weather. Researchers at Berkeley Lab are testing materials that battle that effect, making pavements cooler and safer.
The Merriam-Webster Dictionary defines astronomy as “the science of objects and matter beyond the Earth’s atmosphere”, and astrology as “divination based upon the supposed influence of the stars upon human events”. Now let’s break this down below, not too much, but enough for you to see, through pure language, how obvious the difference is.
Astronomy: “The science”[also defined as “an area of knowledge that is an object of study”, or “knowledge covering general truths or the operation of general laws especially as obtained through the scientific method”. Scientific method is, to put very simply, “finding and stating a problem, the collection of facts through observation and experiment, and the making and testing of ideas that need to be proven right or wrong.”] “of objects and matter beyond the Earth’s atmosphere.” So, to generally state, astronomy is a science based off of facts and findings, that are continually tested until proven true or false, concerning very real and solid objects and matter within the universe outside of our own planet.
Astrology: “Divination” [defined as “the art or practice of using omens or magic powers to foretell the future”] “based upon the supposed” [with supposed defined as “mistakenly believed”] “influence of the stars upon human events.” Which is very simply stated as practicing with superstitious and immensely exaggerated “magic” and/or “omens” to make generalized, and baseless, predictions for universally microscopic humans depending on our perceived position[s] of the [annual and daily] stars, constellations, and “heavenly bodies” of our night skies/celestial sphere.
In comparison, on one hand you have a science concerning the stars, and other celestial bodies, outside of Earth’s own atmosphere and how they exist and coexist within their respected “systems”. On the other hand you have an “art”, of sorts, based upon superstitious and fallible predictions of individual human lives that are assumably determined by the stars and planets in relation to their positions within our skies.
In ancient times astrology was so commonplace during the beginnings of astronomy that astronomers and astrologers were usually one in the same, and “well versed” in both subjects and practices. Although nowadays, thanks to the continuous advancements of the science world and our growing knowledge of the universe, astrology may seem a bit silly and childish, but it’s quite easy to understand, when looking into the origins of astronomy, why astrology was originally so popular and quickly accepted by our ancestors.
The sun and moon in our sky clearly influence our lives in many ways, from determining seasons to causing the tides, as well as determining the daily amount daylight and darkness. The lunar phases even happen to coincide with many biological cycles, such as crops. Of course, when looking into the night sky, our ancestors observed the planets alongside the plethora of stars, including our own, and to them it seemed reasonable to assume they influenced our lives in just as many ways, if not more. Unbeknownst to them, their initial assumptions were correct, aside from positions of stars and planets directly effecting the social/personal aspects of human life, and would remain undiscovered for many years until our understanding of our solar system, and astronomy itself, evolved on many levels.
Now we recognize the ideas of things like energy and gravity that explain the influences of our Sun and Moon, which also prove, with modern science, that the other planets are too far from us astronomically to have any significant infleunce on our own planet, or anything biological including ourselves and our lives. The data is shown below via this post here:
ON THE GRAVITATIONAL EFFECTS OF THE PLANETS, FROM NASA’S WEBSITE:
Here is a table of tidal forces of the Sun, Moon, and Planets. With the Sun’s tidal force equal to 1.00, the following values are given in Thompson (1981):
- Moon: 2.21
- Sun: 1.00
- Venus: 0.000113
- Jupiter: 0.0000131
- Mars: 0.0000023
- Mercury: 0.0000007
- Saturn: 0.0000005
- Uranus: 0.000000001
- Neptune: 0.000000002
- Pluto: 0.0000000000001
ON THE MAGNETIC EFFECTS OF THE PLANETS, FROM WIKIPEDIA:
Others have proposed conventional causal agents such as electro-magnetism within an intricate web of planetary fields and resonances in the solar system. Scientists dismiss magnetism as an implausible explanation, since the magnetic field of a large but distant planet such as Jupiter is far smaller than that produced by ordinary household appliances.
Astrology has fallen by the wayside and has become a children’s topic compared to modern scientific endeavours and achievements. With the constant testing and re-testing associated with true science, astrology fails to meet the constantly-questioning requirements of scientific thinking and skepticism.
While it’s roots are easily understandable, considering the limited resources our ancestors had access to, you can now hopefully see why scientists, teachers, and science enthusiasts alike get upset when one mistakes astronomy for astrology and vice versa. With the ever advancing evolution of science, particularly astronomy, astrology became known as a “pseudo-science” of laughable proportions due to it’s archaic basis that did not evolve respectably over the course of history through solid scientific methods. Now that you know the difference, I hope you continue to improve your own personal methods of scientific thinking, questioning, and skepticism, as well as straying from taking pseudo-sciences such as astrology as seriously as many people mistakenly still do.
Simple House Hold Science Trick: Borax Slime
This one I have personally done many times!
- White Glue Paste (most different variations will work)
- 2 cups/bowls
- food colouring (optional)
- Borax Powder (available in most supermarkets, in the Laundry department)
- add one tablespoon of borax to half a cup of water, stir it well and then set it aside.
- In the other cup/bowl add about 80ml (3oz or 1/3cup) with 20ml of water (3 table spoons)
- add food colouring (Note* be careful using red, it comes out pink. I made that mistake… twice.) and stir.
- add one tablespoon of the Borax/water solution to the entire Glue/water solution and stir.
- Let it sit for about half a minute.
- Have Fun! (if you have no other uses for the left over ingredients, try using different amounts to make different consistencies, or even multiply all the amounts evenly to make one giant blob!)
Light strikes the retina located in the back of our eyes, allowing us to see. Within the retina are neurons that transmit a signal to the brain when they are stimulated with light. Seen here is the surface of the retina from a mouse, with neurons converging towards the optic disc (bottom), the location where neurons exit the eye towards the brain.
Image by Dr. Alejandra Bosco, University of Utah.
Today’s guest and author of Gulp: Adventures on the Alimentary Canal, Mary Roach in Popular Science:
Taste is a sort of chemical touch. Taste cells are specialized skin cells. If you have hands for picking up foods and putting them in your mouth, it makes sense for taste cells to be on your tongue. But if, like flies, you don’t, it may be more expedient to have them on your feet. “They land on something and go, ‘Ooh, sugar!’ ’’ Rawson does her best impersonation of a housefly. “And the proboscis automatically comes out to suck the fluids.” Rawson has a colleague who studies crayfish and lobsters, which taste with their antennae. “I was always jealous of people who study lobsters. They examine the antennae, and then they have a lobster dinner.”
The study animal of choice for taste researchers is the catfish, simply because it has so many receptors. They are all over its skin. “They’re basically swimming tongues,” says Rawson. It is a useful adaptation for a limbless creature that locates food by brushing up against it; many catfish species feed by scavenging debris on the bottom of rivers.
I try to imagine what life would be like if humans tasted things by rubbing them on their skin. Hey, try this salted caramel gelato—it’s amazing.
Image by Emily Cavalier