Ghrelin is a hormone produced mainly by P/D1 cells lining the fundus of the human stomach and epsilon cells of the pancreas that stimulates hunger. Ghrelin levels increase before meals and decrease after meals. It is considered the counterpart of the hormone leptin, produced by adipose tissue, which induces satiation when present at higher levels. In some bariatric procedures, the level of ghrelin is reduced in patients, thus causing satiation before it would normally occur.
Leptin is a 16 kDa protein hormone that plays a key role in regulating energy intake and energy expenditure, including appetite and metabolism. It is one of the most important adipose derived hormones. The ''Ob(Lep)'' gene (Ob for obese, Lep for leptin) is located on chromosome 7 in humans.
The effects of leptin were observed by studying mutant obese mice that arose at random within a mouse colony at the Jackson Laboratory in 1950. These mice were massively obese and excessively voracious. [...]
Leptin and ghrelin seem to be the big players in regulating appetite, which consequently influences body weight/fat. When we get hungrier, we tend to eat more. When we eat more, obviously, we maintain our body weight or gain that weight back.
Both leptin and ghrelin are peripheral signals with central effects. In other words, they’re secreted in other parts of the body (peripheral) but affect our brain (central).
Leptin is secreted primarily in fat cells, as well as the stomach, heart, placenta, and skeletal muscle. Leptin decreases hunger.
Ghrelin is secreted primarily in the lining of the stomach. Ghrelin increases hunger.
Both hormones respond to how well-fed you are; leptin usually also correlates to fat mass — the more fat you have, the more leptin you produce. Both hormones activate your hypothalamus (a part of your brain about the size of an almond).
And here’s an important point: both hormones and their signals get messed up with obesity.
While many eyes in the commercial airline industry were undoubtedly watching the U.S. Navy's EMALS (Electromagnetic Aircraft Launch System) testing, it is Airbus that has first stepped forward suggesting commercial applications. Earlier this year the manufacturer announced "Smarter Skies," a series of concepts and promotional videos revealing where they want to be by 2050.
One component in their plan is for an EMALS-like system, though they never directly refer to military subcontractor General Atomics' invention; instead the company calls it "Eco-Climb," writing that "Aircraft could be manoeuvred onto a track system and accelerated using either electro-magnetic motors built into the track or an inductive circuit within the aircraft itself." [...]
Aircraft could be manoeuvred onto a track system and accelerated using either electro-magnetic motors built into the track or an inductive circuit within the aircraft itself.
Acceptable acceleration and deceleration limits of passengers would need to be determined, but the experience would be more akin to a comfortable children’s funfair ride rather than a high-octane white knuckle theme park.
The ultimate, albeit it very extreme, concept is to have a system that not only launches but also captures the aircraft, removing the need for landing gear. This would require all airports to have the same system, to accommodate all routes along with alternative/diversion airports, and most likely is beyond 2050.
Electromagnetic Aircraft Launch System (EMALS) is a complete launch system designed to replace the existing steam catapult currently being used on aircraft carriers. The USS Gerald R. Ford, the first ship of the CVN-21 Future Aircraft Carrier Class, will use electromagnetic launch systems.
The last typewriter to be made in the U.K. has rolled off the production line -- and straight into London's Science Museum.
Brother has been making typewriters in the U.K. since 1985, the BBC reports, producing 5.9 million typewriters at its Wrexham factory. Since the advent of computers, demand has gone down. Way down.
The last typewriter will join 200 others in the Science Museum's collection. "This object represents the end of typewriter manufacture in the UK, a technology which has developed over the last 130 years and has been important to so many lives," said Rachel Boon, assistant curator of technologies and engineering. "This model will enable us to tell the story of how technology has evolved in accordance with our communication needs."
Brother stopped making typewriters in Britain because demand had
fallen so much in the country, but it still sells Asian-made machines to
the US market.
From as early as 1714, inventors were tinkering about with various
"writing machines" and patenting their efforts, but none of the early
inventions got much interest. It wasn't until Remington, then a
manufacturer of sewing machines, signed an agreement with a patent
holder in the 1870s that the Sholes and Glidden Type-writer was born,
coining the name and the QWERTY layout that would prove so popular.
Brother started manufacturing portable typewriters in the 1960s and produced its first electronic typewriters in 1985.
It has been almost 40 years since the Apollo 17 mission last landed a man on the moon. It may not take anywhere near that long before we send astronauts back to the moon's neighborhood.
Space.com reports that NASA is seriously looking at sending out a new manned moon mission with the purpose of creating a manned outpost beyond the far side of moon and eventually visiting an asteroid in 2025. This may not physically land a human on the moon, but it would establish a deep space outpost as a base for research and missions.
Artist's concept of astronauts in an Orion capsule helping direct robotic teleoperations on the moon's farside. CREDIT: Lockheed Martin
"NASA has been evolving its thinking, and its latest charts have inserted a new element of cislunar/lunar gateway/Earth-moon L2 sort of stuff into the plan," Logsdon told SPACE.com. (The Earth-moon L2 is a so-called libration point where the two bodies' gravitational pulls roughly balance out, allowing spacecraft to essentially park there.) [Gallery: Visions of Deep-Space Station Missions]
The Lagrange points for the Earth-moon system. NASA is evaluating an early mission with the Orion capsule placed at Earth-moon L2. Astronauts parked there could teleoperate robots on the lunar farside. CREDIT: David A. Kring, LPI-JSC Center for Lunar Science and Exploration
What if astronauts were to return to the moon? Decades after man first landed on the moon, Space.com is reporting that it’s possible.
A space policy expert told the website that plans are in the works by NASA to travel back to the vicinity of the moon and create a manned outpost there in order to learn more about future deep-space travel. The manned outpost could eventually be used as a staging area for future missions to the moon. This morning on "Early Start," fmr. Astronaut and International Space Station Commander Leroy Chiao explains.
50 years ago, President John F. Kennedy told the United States that man would go to the moon. Soon, another American president may announce that the same celestial body will serve as a waypoint for manned space exploration. The Verge has learned that NASA intends to deploy a robotic lunar rover on the Moon in 2017 to search for water and other resources necessary for space travel, and that NASA may have secured support from the White House for an actual manned outpost — a space station — floating above the far side of the moon. Rumors of such a deep-space outpost surfaced as early as February of this year, when a leaked memo from a NASA administrator detailed an idea to build a "human-tended waypoint" at Earth-Moon Lagrange Point 2 (EML-2): a point in space where balanced gravitational forces allow an object to remain in stationary orbit relative to both the Earth and the Moon. From there, NASA could launch missions deeper into space — say, to Mars, or a near-Earth asteroid — using the base as a stepping stone.
Clinging with root-like "rhizoids" to the soft, muddy sediment, the harp sponge captures tiny animals that are swept into its branches by deep-sea currents. Typically, sponges feed by straining bacteria and bits of organic material from the seawater they filter through their bodies. However, carnivorous harp sponges snare their prey—tiny crustaceans—with barbed hooks that cover the sponge's branching limbs. Once the harp sponge has its prey in its clutches, it envelops the animal in a thin membrane, and then slowly begins to digest it.
The harp sponge's unusual shape and exposure to currents may also help it to reproduce more effectively. The swollen balls at the tip of the sponge's upright branches produce packets of sperm. These sperm packets are released into passing currents and are captured on the branches of other nearby sponges. The sperm then works its way from the packets into the host sponge to fertilize its eggs. As the fertilized eggs mature, these contact sites swell up, forming bulges part way up the host sponge's branches (see photo).