21 year old Nigerian. German major, Chemistry minor. Premed. Science lover and lover of language. German, virology, epidemiology, nuclear chemistry, orgo you name it!
The phenomenon shown in this shot is called guttation, the exudation of tiny drops of xylem sap that accumulate on the tips or edges of leaves some vascular plants, such as grasses. It is different to dew, which condenses from the atmosphere onto the plant surface.
In May 2008, Chile’s Chaiten volcano violently erupted, spewing out clouds of dirty ash and illuminating the dark sky with a most unusual kind of lightning.
Photographer Carlos Gutierrez captured the dramatic nighttime display—in which green lightning emerged from the ash cloud—in the striking image above.
The origin of the bright green lightning bolts remained a mystery until atmospheric scientist Arthur Few, of Rice University in Houston, became curious about the phenomenon. “I thought, ‘That’s funny; why don’t we see this in lightning storms?’” said Few at the meeting of the American Geophysical Union (AGU) in San Francisco on Monday.
Although green lightning seems unusual, Few now suspects it occurs during all thunderstorms but is concealed inside clouds.
The concealment results from the structure of storm clouds. On the inside, the clouds contain ice crystals that are either positively or negatively charged. Surges of electricity occur between positively and negatively charged regions within the cloud—lightning—but they remain inside, unseen by even the most committed storm chasers.
In contrast, volcanic ash clouds carry their electrical charges on the outside, where they are sparked by fragments of rock forcefully ejected into the air during an eruption.
Few thinks that the bright green bolts seen at the Chaiten volcano are simply “positive streamers,” or a current-transferring electrical surge from a positively to a negatively charged region on the outside of the cloud.
If only we could see inside thunderclouds, he suggests, we would see green lightning more often.
Green Color Explained
But why green? The green hue is given off by electrically excited oxygen atoms, says Few. He thinks the same process paints the sky green during the vivid light shows of the aurora borealis that can dominate northern skies in winter.
This phenomenon may have also colored the tail of Comet Lovejoy as it passed overhead in November.
For the time being, however, Chaiten in Chile is the only volcano where green lightning has been photographed.
Blood clot by James Archer
A thrombus, or blood clot, is the final product of the blood coagulation step in hemostasis.
Blood clotting is an important mechanism to help the body repair injured blood vessels.
Blood consists of:
-red blood cells containing hemoglobin that carry oxygen to cells and remove carbon dioxide (the waste product of metabolism)
-white blood cells that fight infection
-platelets that are part of the clotting process of the body
-blood plasma, which contains fluid, chemicals and proteins that are important for bodily functions.
Complex mechanisms exist in the bloodstream to form clots where they are needed. If the lining of the blood vessels becomes damaged, platelets are recruited to the injured area to form an initial plug. These activated platelets release chemicals that start the clotting cascade, using a series of clotting factors produced by the body. Ultimately, fibrin is formed, the protein that crosslinks with itself to form a mesh that makes up the final blood clot.
Blood clots are healthy and lifesaving when they stop bleeding. However, blood clots can also form abnormally, causing a heart attack, stroke, or other serious medical problems.
Most heart attacks and strokes result from the sudden formation of a blood clot on a waxy cholesterol plaque inside an artery in the heart or brain. When the plaque ruptures suddenly, thrombogenic substances inside the plaque are exposed to blood, triggering the blood clotting process.
Ok, so a quick explanation of what “Killer T” or cytotoxic lymphocytes are so I can finish studying lol. For the people who asked, cytotoxic t cells are cells of the (Adaptive) immune system that attack and destroy (by releasing molecules that poke holes in the target cells or cause cells to undergo apoptosis [a.k.a. cell suicide]) the cells that display their cognate antigen. It’s important that the cells have not only their cognate antigen but that their C.A. must be presented by something called an MHC class I molecule. MHC (major histocompatibility complex) it just is basically a cell protein complex that their cognate antigen will be bound to. A cognate antigen is a foreign molecule that is recognized by a specific antibody. Killer T cells are basically boss and pretty awesome once you begin to study immunity. Actually I think most people have heard of Natural Killer cells, cytotoxic T’s are very similar but NK cells don’t need a cognate antigen or the MHC molecule or w.e. they just attack cells that have been “marked” (opsonized) for destruction. I just kind of informally introduced them but if you wanted to learn more, I’ll put some links at the bottom of this and if you want me to write me (I could write a book!) just message me and remind me after finals :) So totally remind me to expand on this and explain things, sorry to be a dick and just kind of throw terms and stuff at you!
Oh and I totally stole those pictures from here
You and I both have the ability to travel back in time… at least in our minds. For example, I can remember that last Monday, I was at my desk, writing a post about stomachless animals. You too have a seemingly endless catalogue of the whats, wheres and whens of your life.
This ability to remember the what, where and when of our past experiences is known as “episodic memory”. The term was first coined in the 1970s by Canadian psychologist Endel Tulving, who thought that such memories depended on language and were unique to humans.
He was wrong. In 1998, Nicky Clayton from the University of Cambridge published the first of many seminal experiments with western scrub-jays, showing that they can remember where they had stored food and which hoards were freshest. In other words, these bird brains also have episodic-like memories. We say “episodic-like” since we can’t really know if the animals store their what-where-when information into single coherent memories in the way that we do. Still, it’s clear that the components are there.
Since then, the episodic-like memory club has grown to include the great apes, rats, hummingbirds, and pigeons. But these are all mammals and birds. Christelle Jozet-Alves from Normandie University wanted to know if the same skills existed in animals that are very different to these usual suspects. She turned to the common cuttlefish (Sepia officinalis).
Like octopuses and squid, cuttlefish are cephalopods—a group of animals known for their amazing colour-changing skin and sophisticated intelligence. Cuttlefish are separated from birds and mammals by almost a billion years of evolution. But Jozet-Alves, together with Clayton and Marion Bertin, has shown that they too can “keep track of what they have eaten, and where and how long ago they ate”.
They are also soft-bodied and nutritious, which puts them on the menu of virtually every major group of ocean predator. Cuttlefish deal with these manifold threats through camouflage, defensive ink, and just plain-old hiding. They spend more than 95 percent of their time hiding in safe places. When they do venture out to search for food, it pays them to be quick about it. “Cuttlefish live fast and die young. They live less than two years, but their size drastically increases between hatching and old age,” says Jozet-Alves. “They definitely need to be very efficient when foraging if they want to grow as fast as possible.”
First, the team trained three cuttlefish to approach a black-and-white symbol to get a morsel of food—either crab, which they were fine with, or shrimp, which they vastly preferred. The cuttlefish also learned that the shrimp supply took a while to refill. If they approached the symbols within 3 hours of their last meal, they got nothing.
Next, Jozet-Alves presented them with two of the same symbols at different positions in their tank. The cuttlefish randomly approached one of the symbols, and Jozet-Alves dropped shrimp in front of one, and crab in front of the other.
She tested them an hour later. At this time, it would have been pointless to approach the shrimp symbol, since it wouldn’t have replenished. And the cuttlefish knew that—they almost always approached the crab symbol the second time around. But if Jozet-Alves tested them three hours later, they almost always approached the shrimp symbol instead. They knew that their favourite morsel would have replenished and that it was worth trying for it.
Like terrifying glow-in-the-dark toys, these animals luminesce at night, thanks to a cuticle that absorbs ultraviolet light reflected from the moon and emits a greenish-blue glow. Their luminescence may be part of a warning system that lets them know when the moonlight is so bright they risk being seen by other predators. It would be good to stay out of the way of those predators, since many of them are other scorpions: a scorpion’s diet is 40 per cent scorpion. The glow may also attract another of the scorpion’s favourite snacks, the moth.
(Image: Fabio Pupin/FLPA)