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).
I.B.M.scientists are reporting progress in a chip-making technology that is
likely to ensure that the basic digital switch at the heart of modern
microchips will continue to shrink for more than a decade.
The advance, first described in the journal Nature Nanotechnology on
Sunday, is based on carbon nanotubes — exotic molecules that have long
held out promise as an alternative to silicon from which to create the
tiny logic gates now used by the billions to create microprocessors and
Carbon nanotubes are tiny wires that can conduct digital computer signals at five or 10 times the speed of traditional silicon chips. They have been around since the 1990s, but researchers have had a tough time getting them to behave. When they try to line these wires together in a useful grid as part of a computer design, the wires have a tendency to behave like wet spaghetti noodles.
[...] For the first time since research began on these carbon nanotubes, IBM has succeeded in placing them with near-perfect accuracy on the surface of a silicon chip in order to make electronic circuits.
Guha said the accomplishment is big one, though there are several obstacles that still stand in the way of mass production.
If those challenges are met, then we will see a huge leap in computing performance, as microprocessors for everything from PCs to smartphones will be able to take advantage of the technological advance. They could have applications in integrated circuits, energy storage and conversion, biomedical sensing, and DNA sequencing.
This phenomenon is sometimes called “presentiment,” as in “sensing
the future,” but Mossbridge said she and other researchers are not sure
whether people are really sensing the future.
“I like to call the phenomenon ‘anomalous anticipatory activity,’”
she said. “The phenomenon is anomalous, some scientists argue, because
we can’t explain it using present-day understanding about how biology
works; though explanations related to recent quantum biological findings
could potentially make sense. It’s anticipatory because it seems to
predict future physiological changes in response to an important event
without any known clues, and it’s an activity because it consists of
changes in the cardiopulmonary, skin and nervous systems.”
The study, “Predictive Physiological Anticipation Preceding Seemingly
Unpredictable Stimuli: A Meta-Analysis,” is in the current edition of
Frontiers in Perception Science. In addition to Mossbridge, co-authors
of the study include Patrizio Tressoldi of the Università di Padova,
Padova, Italy, and Jessica Utts of the University of California,
There’s growing buzz about data gleaned by NASA’s Curiosity rover on Mars, specifically over the issue of methane detection on the Red Planet.
On one hand, methane can be geological in origin. But then there’s the prospect that the gas is biotic, or caused by living organisms — meaning it could be the gaseous residue of long-extinct microbes or even the output of Martian organisms alive and well today.
The main instrument for the rover’s astrobiology research is the gold-plated Sample Analysis on Mars (SAM), which includes three complex lab tools and is the largest and heaviest (at 88 pounds, or 40 kilograms) on Curiosity. Many of its capabilities are brand-new or significant improvements on the Viking instruments. [5 Bold Claims of Alien Life]
The principal investigator for SAM is Paul Mahaffy of the Goddard Spaceflight Center, who has worked to put together the instrument for more than eight years. He and other NASA scientists are quick to explain that finding organics on Mars will be very hard to do, and that it’s difficult to find organic carbon in rock samples even on Earth. But he sees some real opportunities.
Recent evidence, however, emphasizes that the methane really is there. The Thermal Emission Spectrometer on the Mars Global Surveyor, an orbiting satellite that collected data from 1996 until 2006, detected relatively high levels of methane in Mars’ atmosphere. MGS revealed that Mars’ methane levels vary by location and season: they are highest in summer and autumn, in regions with volcanoes or other geothermal activity. Chris McKay, a Mars specialist at NASA, told SPACE.com, ”Methane on Mars should have a lifetime of 300 years and should not be variable. If it is variable, this is very hard to explain with present theory. It requires unexpected sources and unexpected sinks.”
This makes it sound like the methane is produced by geology, not biology, but scientists are skeptical that geological processes can account for the quantity and variability of methane found. “Methane is really quite a rare gas in hydrothermal/volcanic exhalations,” Dirk Schulze-Makuch, an astrobiologist at Washington State University, said in an interview with SPACE.com.
“Based on evidence, what we do have is, unequivocally, the conditions
for the emergence of life were present on Mars — period, end of story,”
said Michael J. Mumma, a senior scientist for NASA at the Goddard Space
Flight Center in Greenbelt, Md., who led one of three teams that have
made still-controversial claims of detecting methane in Mars’s
atmosphere. “So life certainly could have arisen there.”
PHILADELPHIA — The colors of a butterfly’s wings are unusually bright and beautiful and are the result of an unusual trait; the way they reflect light is fundamentally different from how color works most of the time.
A team of researchers at the University of Pennsylvania has found a way to generate this kind of “structural color” that has the added benefit of another trait of butterfly wings: super-hydrophobicity, or the ability to strongly repel water.
[...] the team exploited microphase separation of crosslinked polymer chains from nonsolvents to generate nanoroughness (≤120 nm) on holographically patterned diamond photonic crystals.
The process of formation of these nanoroughened patterns consists out of spin-coating, pre-exposure bake, exposure, post-exposure bake (PEB), development, solvent rinsing and critical-point drying (CPD). The pattern is etched with the use of a laser which etches a 3D cross-linked pattern in a kind of material called photoresist. A solvent then washes away all the photoresist untouched by the laser, creating the 3D structure that affects light to create the color effects.
Bio-organisms often exhibit an exquisite array of hierarchical organization with multiscale structures as exemplified by the iridescence in blue Morpho rhetenor butterflies, the waveguiding properties in diatom exoskeletons, the self-cleaning ability of lotus leaves, and the dry adhesion of Gecko foot hairs. These examples provide inspiration for the development of new functional hybrid materials. To mimic hierarchical organization in Nature, one of the emerging strategies is the convergence of top-down microfabrication and bottom-up nanoassembly.
RO: Can you give us an idea of what this material would actually look like when applied to a large surface like, say, an office building or a house? Would it really have that same intense, shimmering quality that we associate with peacock feathers and butterfly wings? Yang: Yes. Since the structural color is a reflective color that is dependent on the structure, it does not suffer photobleaching like pigmentation. As long as the structure maintains its integrity, we will always see the intense shiny color from these materials. However, to fabricate the 3D photonic structures reported in our paper, we used a state-of-art non-conventional 3D lithography technique. So it is not intended for low-cost, large area fabrication. We believe that the concept we demonstrated here is applicable to other fabrication methods. RO: Aside from its potential use in beautifying the outsides of buildings, have you imagined any other potential uses for such this material, or is that something you plan on leaving to the marketing experts? Yang: It could be used as a traffic sign, which needs to be shiny and clean in the rainy or snowy days. It could be used as a bulletin board on the highway or on the building. It could be used as a fancy, protective cover of the iPhone or iPad. It could also be used as camouflage or something that could be worn by the soldiers, for example, as blast injury dosimeters.
We are currently looking into new methods that will allow us to mass-produce these materials for potential commercialization. Of course, we welcome any suggestion from experts about market needs.
Long thought to be bone dry, the moon has recently been confirmed as relatively water rich. But a big question remains: Where did the wet—or more accurately, icy—stuff come from?
A new study might have the answer: The moon's water may have, in a sense, sailed in on the solar wind. The discovery hints at a previously unknown method of delivering water to the inner solar system—and a new way to produce water and rocket fuel for future space missions.
So where does the water come from? Two main theories have been suggested.
Water could be delivered to the moon by the impacts of meteorites and comets, which can contain large amounts of ice.
Another theory is based on the fact hydrogen atoms reach the moon as a result of the solar wind – the continuous stream of particles ejected from the sun. The theory goes that hydrogen atoms then react with oxygen in the surface minerals to form water and hydroxyl
The new study, published by Yang Liu from the University of Tennessee and colleagues, seeks to distinguish between these two theories by looking at the isotopic composition of the hydrogen.
Analysis of the Apollo moon samples, which began in the 1970s, previously had uncovered the presence of hydrogen inside volcanically produced glass beads in the soil. In 2008, scientists found hydrogen in a phosphate mineral in lunar rocks, and last year found it again inside another mineral, olivine.
Three robotic probes, including NASA's LCROSS experiment, also have found evidence for water ice on the moon. But where the water came from has been a mystery.
Using two new techniques to dig down into chemistry of hydrogen inside lunar soil grains, Liu and colleagues determined that most of it came from the solar wind, a steady stream of charged particles from the sun that permeates and defines the boundaries of the solar system.
The solar wind streams off of the Sun in all directions at speeds of about 400 km/s (about 1 million miles per hour). The source of the solar wind is the Sun's hot corona. The temperature of the corona is so high that the Sun's gravity cannot hold on to it. Although we understand why this happens we do not understand the details about how and where the coronal gases are accelerated to these high velocities. This question is related to the question of coronal heating.
In the spring, bee hives get so rich with honey, so crowded with baby bees, they often burst in two. Some bees stay in the original nest with a new queen, but a second group, led by the old queen, heads off to establish a new home. If there's a cloud of bees hanging by a tree branch in your back yard, that's them — the house hunters.
How do they choose a new home?
Ah, says Cornell professor Thomas Seeley, this is the beautiful part: The queen doesn't say, "Here's where we're going!" She's not in charge. The decision is made collectively, bottom-up, and it's done by "voting."
Bees are natural democrats. They've been shaped that way by evolution, plus they've got this spectacular, secret extra ingredient [...]
When honeybees seek a new home, they choose the best site through a democratic process that humans would do well to emulate, according to a Cornell biologist. (Credit: iStockphoto/Irina Tischenko)
The bee's decision-making process is similar to how neurons work to make decisions in primate brains, Seeley says. In both swarms and brains, no individual bee or neuron has an overview, but with many independent individuals providing different pieces of information the group achieves optimal decision-making. Ants similarly organize themselves to make collective decisions, Seeley said.
"Consistencies like these suggest that there are general principles of organization for building groups far smarter than the smartest individuals in them," Seeley writes.
Humans can learn much about democratic decision-making by looking at bees, Seeley says. If the members of a group have common interests, such as the bees in a swarm, then the keys to good collective decision-making are to ensure the group contains diverse members and an impartial leader -- and conducts open debates.
My analyses of collective decision-making by honey bee colonies indicate that a group will possess a high level of SI if among the group’s members there is:
1) diversity of knowledge about the available options,
2) open and honest sharing of information about the options,
3) independence in the members’ evaluations of the options,
4) unbiased aggregation of the members’ opinions on the options, and
5) leadership that fosters but does not dominate the discussion.
Future explorations will examine when a group benefits from using the organizational mechanisms of SI (distributed data collection, collective information processing, and democratic choice) or when a group is better off being led by high-performing individuals.
Seeley, T.D. 1995. The Wisdom of the Hive. Harvard University Press.
Seeley, T.D. 2010. Honeybee Democracy. Princeton University Press.
"We are claiming that mice have limited versions of the brain and behavior traits for vocal learning that are found in humans for learning speech and in birds for learning song," said Duke neurobiologist Erich Jarvis, who oversaw the study. The results appear Oct. 10 in PLOS ONE and are further described in a review article in Brain and Language.
The discovery contradicts scientists' 60-year-old assumption that mice do not have vocal learning traits at all. "If we're not wrong, these findings will be a big boost to scientists studying diseases like autism and anxiety disorders," said Jarvis, who is a Howard Hughes Medical Institute investigator. "The researchers who use mouse models of the vocal communication effects of these diseases will finally know the brain system that controls the mice's vocalizations."
Jarvis acknowledged that the findings are controversial because they contradict scientists' long-held assumption about mice vocalizations. His research suggests the vocal communication pathways in mice brains are more similar to those in human brains than to sound-making circuits in the brains of chimpanzees and other non-human primates. The results also contradict two recent studies suggesting mice do not match pitch or have deafness-induced vocalization changes.
Male mice may learn to match other males' ultrasonic squeaks to get the girls. Credit: iStock.
In the study, funded by HHMI, NSF and NIH, Arriaga first used gene expression markers, which lit up neurons in the motor cortex of the mice's brain as they sang. Arriaga then damaged these song-specific neurons in the motor cortex and observed that the mice couldnât keep their songs on pitch or repeat them as consistently, which also happened when the mice became deaf.
This image shows the motor cortex neurons that directly project to the brainstem and ultimately control the larynx of male mice. Credit: Gustavo Arriaga and Erich Jarvis, Duke.
Figure 1. Brain systems for vocalization in birds and mammals.
A, Typical ultrasonic song segment (sonogram) of a male B6D2F1/J (BxD) mouse produced in response to presentation of female urine. Multiple distinct syllables (letters) are produced in long sequences (sometimes over 30 sec), but only 1 second is shown so that the frequency contours and nonlinearities of individual units can be resolved. The sonogram was generated from Audio S1.
Audio S1. Example of a normal adult BxD mouse song (audio corresponds to sonogram of USVs in Figure 1A).
Associate Professor; Howard Hughes Medical Institute Investigator
Neurobiology, School of Medicine
Our goal is to understanding the molecular mechanisms that construct, modify, and maintain neural circuits for vocal learning. Vocal learning is the ability to modify or imitate the acoustic structure and sequence of vocalizations and is a critical behavioral substrate for spoken language. Studying these mechanisms requires that we compare the genes, vocal behavior, and associated brain pathways of the few rare groups that have vocal learning with the vast majority of species that do not. [...]
BIG SUN-DIVING COMET DISCOVERED: Astronomy forums are buzzing with speculation about newly-discovered Comet C/2012 S1 (ISON). Currently located beyond the orbit of Jupiter, Comet ISON is heading for a very close encounter with the sun next year. In Nov. 2013, it will pass less than 0.012 AU (1.8 million km) from the solar surface. The fierce heating it experiences then could turn the comet into a bright naked-eye object.
The orbital elements of ISON are so surprisingly similar to that of the Comet of 1680 that it has caused speculation in the astronomy community that the two bodies may have once been one comet. [...] This could develop into a “once in a lifetime” opportunity for spectators in the Northern Hemisphere to witness and photograph a truly great comet.
According to a number of articles that appeared at about the same time, the comet's orbit is taking it nearly directly at the Sun, and will get within 1.4 million kilometers of the Sun's surface in November of next year, which should provide a lot of heat to melt the surface and expel gas from the comet. By January, it will be about 60 million kilometers from Earth.
Comet brightness predictions sometimes exceed their performance. Amateur astronomers of a certain age may remember the Comet Kohoutek hype of 1973 – not quite the 'damp squib' it has been portrayed, since it reached naked eye visibility! Even if C/2012 S1 takes on the same light curve as Kohoutek it is certain to be spectacular, quite possibly a once-in-a-civilisation's-lifetime event.