The Fibonacci Sequence Can Help You Quickly Convert Between Miles And Kilometers

Beautiful Blaschka glass model of a Glaucus sea slug.

These amazing animals can give a painful sting if handled. This is because they feed on colonial cnidarians such as Portuguese man o’ war and store the venomous nematocysts of their prey for self-protection.

Book Lovers Day - Free Aeronautics e-Books from NASA

Quieting the Boom

The Shaped Sonic Boom Demonstrator and the Quest for Quiet Supersonic Flight.

Download it HERE

Elegance in Flight

A comprehensive History of the F-16XL Experimental Prototype and its Role in our Flight Research. 

Download it HERE

Probing the Sky

Selected National Advisory Committee for Aeronautics (NACA) Research Airplanes and Their Contributions to Flight.

Download it HERE

Cave of the Winds

The huge Langley Full-Scale Tunnel building dominated the skyline of Langley Air Force Base for 81 years (1930–2011). Explore how the results of critical tests conducted within its massive test section contributed to many of the Nation’s most important aeronautics and space programs.

Download it HERE

A New Twist in Flight Research

A New Twist in Flight Research describes the origins and design development of aeroelastic wing technology, its application to research aircraft, the flight-test program, and follow-on research and future applications.

Download it HERE

Sweeping Forward

Developing & Flight Testing the Grumman X-29A Forward Swept Wing Research Aircraft.

Download it HERE

Thinking Obliquely

Robert T. Jones, the Oblique Wing, our AD-1 Demonstrator, and its Legacy.

Download it HERE

The Apollo of Aeronautics

The fuel crisis of the 1970s threatened not only the airline industry but also the future of American prosperity itself. It also served as the genesis of technological ingenuity and innovation from a group of scientists and engineers at NASA, who initiated planning exercises to explore new fuel-saving technologies.

Download it HERE

X-15: Extending the Frontiers of Flight

X-15: Extending the Frontiers of Flight describes the genesis of the program, the design and construction of the aircraft, years of research flights and the experiments that flew aboard them.

Download it HERE

Ikhana

Delve into the story of the Ikhana, a remotely piloted vehicle used by NASA researchers to conduct Earth science research, which became an unexpected flying and imaging helper to emergency workers battling California wildfires.

Download it HERE

NASA’s Contributions to Aeronautics, Volume 1

This first volume in a two-volume set includes case studies and essays on NACA-NASA research for contributions such as high-speed wing design, the area rule, rotary-wing aerodynamics research, sonic boom mitigation, hypersonic design, computational fluid dynamics, electronic flight control and environmentally friendly aircraft technology.

Download it HERE

NASA’s Contributions to Aeronautics, Volume 2

Continue your journey into the world  of NASA’s Contributions to Aeronautics with case studies and essays on NACA-NASA research for contributions including wind shear and lightning research, flight operations, human factors, wind tunnels, composite structures, general aviation aircraft safety, supersonic cruise aircraft research and atmospheric icing.

Download it HERE

Interested in other free e-books on topics from space, science, research and more? Discover the other e-books HERE.

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1984

George Orwell

Dublin streetscapes from 1900 (John J. Clarke collection) 

Aristotle’s Wheel Paradox. Can you figure out what the paradox is? (What doesn’t make sense?) More info at http://mathworld.wolfram.com/AristotlesWheelParadox.html

Knowing the 20 Amino Acids is definitely a MUST for the 2015 MCAT 

Amino acids that are usually negative (i.e. de-protonated) at physiological pH:

- Glutamate (E) Glu, and Aspartate (D) Asp

Amino acids that are usually positive (i.e. protonated) at physiological pH:

- Lysine (K) Lye, Arginine ® Arg 

Histidine is sometimes charged at physiological pH. 

physiological pH = 7, Neutral 

This is great :) My favorite is proof by ghost reference, what is yours?

The Blood Of Dragons Could Destroy Antibiotic Resistance

Antibiotic resistance is one of the most pressing problems of our times. Traditional antimicrobial drugs aren’t working the way they used to, and the rise

Antibiotic resistance is one of the most pressing problems of our times. Traditional antimicrobial drugs aren’t working the way they used to, and the rise of “superbugs” could bring about the post-antibiotic age, where easily treatable infections suddenly become life-threatening incurable illnesses.

There have been a slew of new discoveries recently that have revealed brand new ways to turn the tide, but the latest revelation at the hands of a team from George Mason University is a particularly unusual sounding one. As it turns out, we could use the blood of dragons to annihilate superbugs.

No, this isn’t an analogy or a plot line from Game of Thrones. The devil-toothed Komodo dragon – the devious beast from Indonesia – has a particular suite of chemical compounds in its blood that’s pure anathema to a wide range of bacteria.

They’re known as CAMPs – cationic antimicrobial peptides – and although plenty of living creatures (including humans) have versions of these, Komodo dragons have 48, with 47 of them being powerfully antimicrobial. The team managed to cleverly isolate these CAMPs in a laboratory by using electrically-charged hydrogels – strange, aerated substances – to suck them out of the dragons’ blood samples.

Synthesizing their own versions of eight of these CAMPs, they put them up against two strains of lab-grown “superbugs,” MRSA and Pseudomona aeruginosa, to see if they had any effect. Remarkably, all eight were able to kill the latter, whereas seven of them destroyed all trace of both, doing something that plenty of conventional antibiotic drugs couldn’t.

Writing in the Journal of Proteome Research, the researchers write that these powerful CAMPs explain why Komodo dragons are able to contain such a dense, biodiverse population of incredibly dangerous bacteria in their mouths. Although it’s not clear where all these bacteria originally came from, the chemical compounds in their blood ensures that they’ll never be properly infected.

In fact, it was this ability to co-exist with such lethal bacteria that piqued the interest of the researchers in the first place.

“Komodo dragon serum has been demonstrated to have in vitro antibacterial properties,” they note. “The role that CAMPs play in the innate immunity of the Komodo dragon is potentially very informative, and the newly identified Komodo dragon CAMPs may lend themselves to the development of new antimicrobial therapeutics.”

It’ll be awhile before these CAMPs are tested in human trials, but the idea that we’re effectively using dragon’s blood, or plasma, to fight against resurgent diseases is genuinely quite thrilling. Alongside Hulk-like drugs that physically rip bacteria apart, there’s a chance that, with the help of these legendary lizards, we may win this war yet.

Sleep suppresses brain rebalancing

Why humans and other animals sleep is one of the remaining deep mysteries of physiology. One prominent theory in neuroscience is that sleep is when the brain replays memories “offline” to better encode them (“memory consolidation”). A prominent and competing theory is that sleep is important for re-balancing activity in brain networks that have been perturbed during learning while awake. Such “rebalancing” of brain activity involves homeostatic plasticity mechanisms that were first discovered at Brandeis University, and have been thoroughly studied by a number of Brandeis labs including the Turrigiano lab. Now, a study from the Turrigiano lab just published in the journal Cell shows that these homeostatic mechanisms are indeed gated by sleep and wake, but in the opposite direction from that theorized previously: homeostatic brain rebalancing occurs exclusively when animals are awake, and is suppressed by sleep. These findings raise the intriguing possibility that different forms of brain plasticity – for example those involved in memory consolidation and those involved in homeostatic rebalancing – must be temporally segregated from each other to prevent interference.

The requirement that neurons carefully maintain an average firing rate, much like the thermostat in a house senses and maintains temperature, has long been suggested by computational work. Without homeostatic (“thermostat-like”) control of firing rates, models of neural networks cannot learn and drift into states of epilepsy-like saturation or complete quiescence. Much of the work in discovering and describing candidate mechanisms continues to be conducted at Brandeis. In 2013, the Turrigiano Lab provided the first ­in vivo evidence for firing rate homeostasis in the mammalian brain: lab members recorded the activity of individual neurons in the visual cortex of freely behaving rat pups for 8h per day across a nine-day period during which vision through one eye was occluded. The activity of neurons initially dropped, but over the next 4 days, firing rates came back to basal levels despite the visual occlusion. In essence, these experiments confirmed what had long been suspected – the activity of neurons in intact brains is indeed homeostatically governed.

Due to the unique opportunity to study a fundamental mechanism of brain plasticity in an unrestrained animal, the lab has been probing the possibility of an intersection between an animal’s behavior and homeostatic plasticity. In order to truly evaluate possible circadian and behavioral influences on neuronal homeostasis, it was necessary to capture the entire 9-day experiment, rather than evaluate snapshots of each day. For this work, the Turrigiano Lab had to find creative computational solutions to recording many terabytes of data necessary to follow the activity of single neurons without interruption for more than 200 hours. Ultimately, these data revealed that the homeostatic regulation of neuronal activity in the cortex is gated by sleep and wake states. In a surprising and unpredicted twist, the homeostatic recovery of activity occurred almost exclusively during periods of activity and was inhibited during sleep. Prior predictions either assumed no role for behavioral state, or that sleeping would account for homeostasis. Finally, the lab established evidence for a causal role for active waking by artificially enhancing natural waking periods during the homeostatic rebound. When animals were kept awake, homeostatic plasticity was further enhanced.

This finding opens doors onto a new field of understanding the behavioral, environmental, and circadian influences on homeostatic plasticity mechanisms in the brain. Some of the key questions that immediately beg to be answered include:

What it is about sleep that precludes the expression of homeostatic plasticity?

How is it possible that mechanisms requiring complex patterns of transcription, translation, trafficking, and modification can be modulated on the short timescales of behavioral state-transitions in rodents?

And finally, how generalizable is this finding? As homeostasis is bidirectional, does a shift in the opposite direction similarly require wake or does the change in sign allow for new rules in expression?

Around 6 million years ago, the African and Eurasian plates moved together, cutting the Mediterranean Sea off from the Atlantic. Without an influx of water from the Atlantic, evaporation began removing more water from the Mediterranean than rivers could replace. The sea dried out almost completely over the course of a couple thousand years.

About 5.3 million years ago, the Straits of Gibraltar reopened, creating a massive flood into the Mediterranean known as the Zanclean Flood. Water rushed down the straits and into the Mediterranean at speeds as high as 40 m/s (90 mph). At its peak, the Zanclean Flood is estimated to have reached rates 1000 times greater than the volumetric flow rate of the Amazon River. 

A similar breach flood occurred in the Black Sea within the past 10,000 years when the Bosporus became unblocked. That flood likely had a devastating impact on Neolithic societies in the area and may be the inspiration for the floods described in the Epic of Gilgamesh and the Bible. (Image credit: BBC, source)