Caitlin Stier, Author at New 女生小视频 Science news and science articles from New 女生小视频 Wed, 31 Aug 2016 16:17:10 +0000 en-US hourly 1 https://wordpress.org/?v=7.0.6 242057827 Thermal flashlight ‘paints’ cold rooms with colour /article/1968761-thermal-flashlight-paints-cold-rooms-with-colour/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Wed, 29 Feb 2012 18:00:00 +0000 http://mg21328546.200 [video_player id=鈥9NhpwjJh鈥漖Video: Walls turn blue with cold
Feeling chilly?
Feeling chilly?
(Image: <a href="http://www.chriseichler.com">Chris Eichler</a>)

PENNY-PINCHING landlords had better watch out. Their tenants could soon be armed with thermal flashlights that capture a colourful 鈥 and possibly incriminating 鈥 portrait of a room鈥檚 temperature.

The device comes from the , a non-profit group based in Cambridge, Massachusetts, that develops open-source tools to allow ordinary people to investigate environmental issues. A PLOTS team is working with a school-run project in Harlem, New York, to help tackle landlords who offer poorly heated apartments.

Another PLOTS team is developing an underwater tool to detect river pollution. It will start by looking for warm sewage seeps in the Gowanus canal, a polluted New York City waterway.

Standard thermal cameras are prohibitively expensive for ordinary people. Costly sensors mean a camera with the resolution of a budget webcam can set you back thousands of dollars. That鈥檚 because each pixel represents a separate thermal probe.

In contrast, the thermal flashlight prototype costs about $40. What鈥檚 more, it can easily be assembled by someone with no electronics expertise. To prove how easy it is, visitors to the in London last month were shown how to build their own devices by fastening probes and wire to a circuit board. They used recycled VHS cases to house their creations.

鈥淭he thermal flashlight can be easily assembled by someone with no electronics expertise鈥

The thermal flashlight is built around a single infrared thermometer. This scans an area of wall and picks up varying levels of radiation emanating from it. This temperature information is fed into a microprocessor, which controls a multicoloured LED light. Shine the flashlight against a surface and the colour shows you a real-time temperature reading. Areas of the wall with a cooler temperature show up blue, while red light shines on patches that register as warmer. An image of the light-painted room showing exactly where heat is leaking can then be captured using a webcam with an online app called or just standard time-lapse photography.

The team hopes that such pictures can be used to confront landlords who are not insulating their apartments sufficiently. In New York, for example, landlords must make sure their apartments are at 20 掳C if the outdoor temperature falls below 12.8 掳C between 6am and 10pm.

Users can tweak the code that controls the LED鈥檚 sensitivity so it responds to a narrower or wider temperature gradient.

The idea for the device grew out of a hack that created a glowing Roomba vacuum to monitor air quality. For , a PLOTS co-founder who led the London session, such reincarnations are part of the lab鈥檚 citizen-science mission. The thermal flashlight has already led to the birth of different tools, with the Gowanus canal team developing a that directly measures water temperature while kept afloat by plastic bottles gathered from the canal itself.

While the device is sensitive enough to detect the temperature change when a cup of coffee is tipped into the water nearby, the team is now calibrating it so that it can detect much more subtle temperature changes. They intend to test the device on rainy days, when sewage sometimes overflows into the canal.

Jonathan Jesneck, at the Massachusetts Institute of Technology鈥檚 Field Intelligence Lab, says the flashlight is a 鈥渃ute idea鈥 that could perhaps be fused with results from the external that he has worked on. 鈥淚 really like the concept of empowering people to make thermal assessments of their own homes, without the need for expensive thermal cameras or software,鈥 he says.

Wylie wants the project to spawn variations such as a device that maps dangerous levels of formaldehyde in the home. 鈥淲hat we see this tool as doing is basically giving a new kind of sensory access to the user,鈥 says Wylie. 鈥淲e don鈥檛 know all the questions it could be used to answer yet.鈥

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Parasite-plagued flies self-medicate on booze /article/1968386-parasite-plagued-flies-self-medicate-on-booze/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Fri, 17 Feb 2012 17:29:00 +0000 http://dn21493

Video: Parasitic wasp deposits eggs in fly larva

Doctor's orders
Doctor鈥檚 orders
(Image: Denis Bringard/Sunset/Rex Features )

Ever been told to take a swig of whisky to ward off a cold? Boozing fruit fly larvae do something similar: they seek out alcohol to kill a parasitic wasp that lays its eggs in their bloodstream.

Before you reach for the bottle, though, the researchers who found the behaviour caution that flies are very different to us, and their results don鈥檛 say anything about the health benefits of a hot toddy.

The discovery, made by and colleagues at Emory University in Atlanta, Georgia, is one of the few examples of self-medication known in insects 鈥 and a rare health benefit for alcohol.

Fruit fly larvae are raised in rotting fruit and so are naturally resistant to the toxic effects of alcohol. They have evolved enzymes like alcohol dehydrogenase to tolerate the ethanol while getting their fix of fermenting yeast. The flies even have a taste for grapes and are commonly found in wineries.

Alcohol licence

Schlenke and his team raised healthy and parasitised fruit fly larvae (Drosophila melanogaster) in Petri dishes that contained both regular food and food laced with alcohol. The alcohol content was comparable to that of beer.

Eighty per cent of the parasitised larvae favoured the boozy food, compared with just 30 per cent of healthy ones.

The parasites normally eat developing fruit flies from the inside out, but the experiment鈥檚 open bar policy helped flies escape this fate. Parasitic wasps avoided depositing their eggs in booze-soaked fly larvae.

The alcohol appeared to keep the wasps at bay, say the researchers. For their young, the consequences of developing in a boozy environment are 鈥済ruesome鈥, says Schlenke. 鈥淭he wasps die and all of their organs are diverted out through their anus. Their guts actually pop out.鈥

In addition to warding off parasites, the alcohol appeared to have a cleansing effect on flies that were already infected. Infected larvae that consumed alcohol were more likely to survive than teetotallers.

Entomologist of the University of Illinois at Urbana-Champaign advises temperance for humans seeking alcohol as a cure for their ills. 鈥淲e don鈥檛 live in a sea of ethanol so it鈥檚 kind of a different world for us,鈥 she explains. 鈥淲e aren鈥檛 nearly as good as metabolising it as fruit flies.鈥

Journal reference: , DOI: 10.1016/j.cub.2012.01.045

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Boas sense when prey’s heart goes still /article/1967539-boas-sense-when-preys-heart-goes-still/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Wed, 18 Jan 2012 17:30:00 +0000 http://dn21369 [video_player id=鈥漴VQBhkrr鈥漖Video: Watch a boa strangle a rat by sensing its pulse

It takes a lot of effort to squeeze prey to death
It takes a lot of effort to squeeze prey to death
(Image: Scott Boback)

Boa constrictors don鈥檛 like to waste their hugs. A study involving dead mice and fake hearts shows that the snakes loosen their deathly grip once their prey鈥檚 pulse stops.

This reaction allows the snakes to save energy, say and his team at Dickinson College in Carlisle, Pennsylvania.

Boback and his team fed sixteen wild and captive-born snakes on dead rats rigged with artificial hearts that either beat continuously, pumped for ten minutes or were still.

They warmed the rats with an electric blanket to mimic live prey, and implanted two small water-filled bladders in their chest cavity and abdomen to monitor the boas鈥 squeeze. The bladder in the chest cavity was placed right next to the rats鈥 actual heart and hooked up to a piston pump to simulate heartbeats.

The team found that the boas squeezed all rats, but would frequently adjust their hugs and periodically give a tighter squeeze if they sensed a heartbeat. Rats with no pulse were released after 10 minutes and squeezed with half the pressure of those whose heart beat continuously through the 20-minute trial. In experiments where the heartbeat was switched off halfway through, it was a matter of minutes before the snakes released their coils.

Innate behaviour

Captive-bred snakes that had never hunted behaved in the same way as wild ones, so sensing and responding to the prey鈥檚 heartbeat is likely innate, says the team. Just how much force is necessary may be something learned through experience, though聽鈥 wild boas used a looser and shorter grip.

Being economical with their squeeze makes sense for the boas. Studies show that constriction requires a seven-fold increase in aerobic metabolism, so cutting it short means saving energy.

鈥淚t鈥檚 a tremendous expense in terms of onboard fuel to search, find, grab, kill and swallow a prey item聽鈥 not to mention throughout all of it you are very, very vulnerable,鈥 says , another member of the team. 鈥淚t makes a lot of sense to know when to cut your losses, swallow the food and run.鈥

While rats succumb after a minute or two of being trapped in a boa鈥檚 grip, this pulse-sensing ability could also help the snakes check the vital signs of more tenacious prey like lizards, which can survive an hour and a half without oxygen.

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Deepest known ‘black smoker’ vent discovered /article/1967158-deepest-known-black-smoker-vent-discovered/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Tue, 10 Jan 2012 17:35:00 +0000 http://dn21340 [video_player id=鈥漹acoPPea鈥漖Video: Deepest black smoker teems with life
New shrimps and fish on the black smoker block
New shrimps and fish on the black smoker block
(Image: University of Southampton/NOC)

Below the Caribbean Sea lies the deepest hydrothermal vent yet found. At 5000 metres down, the black smoker is 800 metres deeper than its rivals. Despite that it teems with life, including microbial mats, spiny anemones and swarms of a previously unknown species of shrimp that sees using a light sensor on its back.

鈥淎way from the vents, life is very sparse indeed in this part of the world,鈥 says at the University of Southampton, UK, who led the expedition with of Southampton鈥檚 National Oceanography Centre. 鈥淲e came across pretty barren sea floor and then suddenly, bang: you are right in the middle of this really lush colony of deep-sea creatures.鈥

The group first became aware of this Caribbean deep-sea sauna when they scanned the area for chemicals using an autonomous vehicle. They then deployed a second programmable underwater vehicle to investigate the habitat.

The deepest vent was found in the heart of a volcanic rift, but the team also found an unusual vent encased in an undersea mountain some distance away from the ridge. Together these two vent sites provide an isolated lab for researchers to study the migration of vent creatures.

鈥淰enting may be more common around the globe than previously considered,鈥 says of the University of Oxford. 鈥淲e are in an exciting phase of exploration of these ecosystems, where deeper or more remote vents are being sampled. Previous conceptions about vent ecology and biogeography are being found to be overly simple.鈥

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Microscopic origami boxes build themselves /article/1966703-microscopic-origami-boxes-build-themselves/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Tue, 20 Dec 2011 14:14:00 +0000 http://dn21303

Video: Micro-origami folds up on its own

Origami just got microscopic 鈥 and autonomous. It鈥檚 now possible to select the best flat starting shapes for making tiny boxes that build themselves.

This is tough as the number of possible 2D cut-outs is overwhelming. For a simple cube, there are just 11 different options, but a dodecahedron of 12 pentagon faces has 43,380.

A team led by of Johns Hopkins University in Baltimore, Maryland, made hinged nickel cut-outs, edged with alloy, using algorithms to choose the fastest-folding starting shape. Melting the alloy made the shapes fold into boxes less than a millimetre wide. The team found that the least spread-out starting shapes folded fastest.

鈥淲e have lots of cool technology from the chip manufacturing world for printing to 2D forms,鈥 says of the Massachusetts Institute of Technology, who specialises in the mathematics of folding. 鈥淗ow do you nanomanufacture 3D surfaces? This provides a natural way to bridge that gap.鈥

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Lasers create five new ‘stars’ in night sky /article/1957461-lasers-create-five-new-stars-in-night-sky/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Mon, 14 Feb 2011 11:31:00 +0000 http://dn20124
Lasers create five new 'stars' in night sky

Many big observatories point a single laser at the sky to measure atmospheric turbulence. Recently, the Gemini South telescope tested a five-laser system, reports Kelly Beatty of Sky & Telescope magazine.

See more in our gallery: Lasers create five new 鈥榮tars鈥 in night sky

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Neptune ‘dead zones’ hold more rocks than asteroid belt /article/1951574-neptune-dead-zones-hold-more-rocks-than-asteroid-belt/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Thu, 12 Aug 2010 21:10:00 +0000 http://dn19309 Neptune's Trojan asteroids, which share the planet's orbit, may outnumber those in the solar system's main asteroid belt
Neptune鈥檚 Trojan asteroids, which share the planet鈥檚 orbit, may outnumber those in the solar system鈥檚 main asteroid belt
(Image: NASA)

An asteroid that is trapped in a 鈥榙ead zone鈥 behind Neptune has been found for the first time. The finding suggests that the blue planet鈥檚 rock collection may outnumber objects in the main asteroid belt and may provide clues to the origin of comets.

Objects can become trapped in two gravitational dead zones around Neptune, where the forces of the sun and the planet balance out. In the last decade, astronomers have identified six asteroids 鈥 called Trojans 鈥 in the zone that moves in front of the planet along its orbit. But finding Trojans in the region trailing the planet has proved more difficult, because the faint light reflected off of objects there is washed out by brighter starlight from the plane of the Milky Way.

Now, thanks to strategically located dust clouds, at the Carnegie Institution of Washington and Chadwick Trujillo at the in Hawaii have spied the first such trailing Trojan.

Cloudy discovery

To find the asteroid 鈥 dubbed 2008 LC18 鈥 Sheppard and Trujillo used existing images of the sky to identify dark clouds of dust and gas in our galaxy that fall along the path of the trailing Lagrangian point. These clouds blotted out the light from background stars. They used the Subaru Telescope on Mauna Kea, Hawaii, to spot the Trojan as it moved across the sky.

The team estimates that 2008 LC18 is about 100 kilometres wide. Based on the size of the region they studied, they suspect Neptune harbours as many as 150 other Trojans of this size in the trailing Lagrangian region. Together with the projected numbers in the planet鈥檚 leading Lagrangian zone, they suspect Neptune likely holds more asteroids of this size than the solar system鈥檚 main asteroid belt between Mars and Jupiter.

Neptune鈥檚 Trojans were probably captured billions of years ago, when solar system bodies shifted positions in a period of planetary upheaval, Sheppard says. Neptune, which may have been hurled outwards to twice its original orbit in the migration, could have scooped up the rocky bodies as it moved.

Trojan comets?

The Trojans could provide insights into the origin of comets. If Neptune boasts smaller Trojans, they could be a source of short-period comets, which swing through the inner solar system every few hundred years. Dislodged Trojans may account for the comets, whose origin is uncertain, but more will need to be found before their numbers can actually support this scenario.

Automated surveys that take frequent snapshots of the sky, such as the upcoming Pan-STARRS project in Hawaii, will be particularly well-suited to hunt for asteroids in Neptune鈥檚 orbit.

鈥淲hat these projects are all about is making a movie of the whole sky, so they鈥檒l get anything that moves,鈥 says of the University of California, Berkeley, who found the first Neptune Trojan. 鈥淭hat鈥檚 crucial for finding objects like Trojans.鈥

Journal reference: (DOI:10.1126/science.1189666)

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Thank your thalamus for a good night’s sleep /article/1951344-thank-your-thalamus-for-a-good-nights-sleep/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Mon, 09 Aug 2010 15:00:00 +0000 http://dn19277
What is defending your shut-eye?
What is defending your shut-eye?
(Image: Regine Mahaux/Getty)

Do you sleep like a baby? You may have your thalamus to thank, according to research that suggests this brain region helps people sleep through bumps in the night.

To discover why some people can sleep through noise while others awake at the faintest disruption, and colleagues at Harvard Medical School used electrodes to monitor the brain activity of 12 people while they slept in a pitch-black, soundproof room. They then repeated the experiment, this time playing 14 sounds, such as a toilet flushing and street traffic, at 30-second intervals, increasing the volume until the volunteers鈥 brainwaves showed signs of arousal.

Sleepers who tolerated louder sounds before waking showed a higher frequency of 鈥渟leep spindles鈥 鈥 short bursts of activity of specific wavelength 鈥 during non-REM sleep than those who woke more easily.

The spindles arise in the brain鈥檚 sensory relay centre in the thalamus. The team suspects the thalamus acts as a sort of insulator, sending out spindle activity to stop areas of the brain from perceiving and responding to sounds.

Ellenbogen hopes this work will contribute to future solutions to promote these bursts and provide people with a sounder night鈥檚 sleep.

Journal reference: Current Biology, DOI: 10.1016/j.cub.2010.06.032

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Couch-potato orang-utans make most of rainforest fruit /article/1951157-couch-potato-orang-utans-make-most-of-rainforest-fruit/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Mon, 02 Aug 2010 19:00:00 +0000 http://mg20727720.201 1951157 Comet tail confirmed on alien planet /article/1950724-comet-tail-confirmed-on-alien-planet/?utm_campaign=RSS|NSNS&utm_content=currents&utm_medium=RSS&utm_source=NSNS Fri, 16 Jul 2010 12:30:00 +0000 http://dn19185 The roster of weird alien worlds has a new addition: a planet with a tail.

The gaseous extrasolar planet known as HD 209458b has been suspected of having a comet-like tail since 2003 but, being 153 light years away, it has been hard to prove.

Using the Hubble Space Telescope, and his team at the University of Colorado in Boulder has managed to study the mass the planet is shedding. They calculated the tail鈥檚 composition, direction and speed by studying changes in its host star鈥檚 ultraviolet spectra as the planet passes in front of it.

HD 209458b is similar to Jupiter in size and composition. It orbits its star in just 3.5 days and its surface is roughly 1100 掳C. This intense heat is causing heavy elements like carbon and silicon to boil off, and be blown away by the solar wind.

鈥淚t鈥檚 a very similar phenomenon to what happens with a comet,鈥 Linsky explains. 鈥淓xcept it鈥檚 starting off as a gas planet as opposed to ice and the material in its outer atmosphere is being heated and lost. The wind from the star is pushing it away from the planet so we see a tail.鈥

The gas trail is blowing away from the star at more than 35,000 kilometres per hour. The team estimates that the comet-like planet has a trillion years before the entire planet disappears.

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