Biological Sunscreens Tune Polychromatic Ultraviolet Vision in Mantis Shrimp
Michael J. Bok,1,3,* Megan L. Porter,1,4 Allen R. Place,2 and Thomas W. Cronin1
1Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
2Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, 701 East Pratt Street, Baltimore, MD 21202, USA
Stomatopod crustaceans, or mantis shrimp, are renowned for their complex visual systems. Their array of 16 types of photoreceptors provides complex color reception, as well as linear and circular polarization sensitivity [1–6]. The least-understood components of their retina are the UV re- ceptors, of which there are up to six distinct, narrowly tuned spectral types . Here we show that in the stomatopod species Neogonodactylus oerstedii, this set of receptors is based on only two visual pigments. Surprisingly, five of the six UV receptor types contain the same visual pigment. The various UV receptors are spectrally tuned by a novel set of four short- and long-pass UV-specific optical filters in the overlying crystalline cones. These filters are composed of various mycosporine-like amino acid (MAA) pigments. Commonly referred to as ‘‘nature’s sunscreens,’’ MAAs are usually employed for UV photoprotection [7, 8], but mantis shrimp uniquely incorporate them into powerful spectral tuning filters, extending and diversifying their preeminently elaborate photoreceptive arsenal.
Brain imaging confirmed this was the case. Other researchers found that these rewired inputs might be activating neural pain pathways for the missing hand, or at least generating ‘junk’ signals that were interpreted by the brain as a range of sensations – including pain.
It was possible, too, that when signals sent to move the missing hand didn’t lead to any corresponding visual or sensory confirmation of the movement, this dissonance was perceived as pain. The brain is known to emphasise visual feedback over other types – which may also be the reason why passengers get carsick more often than drivers. (When a passenger reads in a car moving along a curvy road, the balance sensors in the inner ear report motion that differs from what the eyes are seeing, and the dissonance is thought to be expressed as nausea. Whereas for the driver, the balance sensors in the ears, the spatial sensors in the body and what the eyes report are all in reassuring agreement.)
Dr Ramachandran and his group wondered if visual feedback of the phantom limb’s movement might help relieve pain in it. They put together what they called the ‘mirror box’ – a simple but ingenious contraption that hid the stump while allowing a reflection of the intact limb to be superimposed over the phantom limb. Now, if the amputee moved the intact and phantom limbs in sync, the brain could ‘see’ the phantom limb move.
The first amputee to try the mirror box reported being able to move his phantom limb for the first time in over a decade, and he felt immediate relief from pain. Subsequent users too found they could manage their phantom pain using the box.
Surgery and medication have been found to be only slightly or not at all effective when dealing with phantom pain. Stephen knew this, and he tried to will his phantom pain away: “Optimism. Mind over matter. I thought I could beat it.” But it kept coming back, and it kept getting worse. “Then I tried to drink it to death, which was costly and messy in every conceivable sense, plus totally ineffective.”
In 2008, Stephen was working as a property manager in south Baja, Mexico, when he had a particularly agonising bout of phantom pain. “I was not presentable for 72 hours,” he says. He was aware of mirror therapy from having looked online for treatments, and he decided to give it a try. He got into his truck and drove two-and-a-half hours to the nearest Home Depot to buy a mirror. He tried it right there in the parking lot, and in five minutes the pain was gone.
Stephen used the mirror for two weeks, then stopped because the pain had not returned. About a year and a half later, he felt the pain again, and this time he stayed the course for the full five weeks. He hasn’t had phantom pain for over four years. “It’s gone now,” he says. “It’s gone because I treated myself with a mirror.”
Many European communities have adopted 30 km/h (about 20 mph) speed limits in urban and/or residential areas. Traffic related deaths and injures drop dramatically - a summary of experiences in the UK.
Cost effective: Total 20 is affordable at £3 per head6. With a road death valued at £1.689m and a serious casualty at £189k a Total 20 policy must only prevent one death or 3 serious casualties to pay back its one off implementation cost for a 190,000 population. Warrington had first year rates of return of 800% on casualty prevention. Active travel increases. Bristol found using a mean of a 23% increase in walking and a 20.5% increase in cycling that for each £1 spent the return on investment for walking is £24.72 and cycling is £7.47 and that cyclist casualty numbers fell by around 40%. Savings from the health economic gains from increased activity outweigh those of casualty avoidance alone by ratio of 1.6:1, even before disability benefits and obesity changes to the next least unfit cohort of people who begin exercising more.
Honda was one of the first Japanese companies to break the American anti-Japanese product stigma. They marketed small motorcycles with a very successful print and later tv campaign. Serious motorcycle people laughed, but Honda was playing a different long term game...
A new study published in the American Journal of Medicine correlates a drop in exercise with increasing obesity over the past 20 years. It is based on NHANES data, which is very high level and relies on self reporting. A central finding is caloric intake was steady over the period.
This is in contrast to several other studies that suggest caloric intake is the culprit. The amount of exercise required to make a significant difference is too high. There are also issues with the types of food eaten .. in short the study of metabolism is very difficult and is still poorly understood.
I'm guessing, not being an expert on the subject, that exercise and intake are both important along with the type of food. To get to the bottom of this you can't rely on self reported data.
Folks looking to improve their vertical jump ... there's an app for that. VERT is a small wearable sensor array with and ARM cpu that measures vertical distance and communicates with iOS devices with Bluetooth 4.0. Basketball and volleyball players use them for training.
Time perception depends on how rapidly an animal's nervous system processes sensory information. To test this ability, researchers show animals a rapidly flashing light. If the light flashes quickly enough, animals (and humans) perceive it as a solid, unblinking light. The animal's behavior or its brain activity, as measured by electrodes, reveals the highest frequency at which each species perceives the light as flashing. Animals that can detect the blinking at higher frequencies are perceiving time at a finer resolution. In other words, movements and events will appear to unfold more slowly to them—think slow-motion bullet dodging in an action movie.
The scientists who ran the new study gathered data from previous experiments on the rate at which visual information is processed in 34 vertebrates, including lizards, birds, fish and mammals. The scientists hypothesized that the ability to detect incoming sights at a high rate would be advantageous for animals that must perform the equivalent of bullet dodging—responding to visual stimuli very quickly to catch elusive prey or escape predators, for instance. These animals tend to be lighter and have faster metabolisms. The data bore out the hypothesis: species that perceived time at the finest resolutions tended to be smaller and have faster metabolisms.
So while sleight of hand helps, it's as much about capturing all of somebody's attention with other movements. Street pickpockets also use this effect to their advantage by manufacturing a situation that can't help but overload your attention system. A classic trick is the 'stall', used by pickpocketing gangs all over the world. First, a 'blocker', walks in front of the victim (or 'mark') and suddenly stops so that the mark bumps into them. Another gang member will be close behind and will bump into both of them and then start a staged argument with the blocker. Amid the confusion one or both of them steal what they can and pass it to a third member of the gang, who quickly makes off with the loot.