When a beam of light hits your eye, a chain of events is set off that is really quite amazing. Kendall J. Blumer (Washington University School of Medicine) describes a little of it in the Jan. 1 issue of Nature.1 You don’t have to understand the following description; just be glad you don’t have to operate your retina in manual mode:Light streaming into the eye is detected by specialized neurons (photoreceptors) in the retina. In response to light, a coordinated series of molecular events � the so-called phototransduction cascade � is triggered in these cells (Fig. 1). Photons excite pigment-containing proteins called rhodopsins, which then switch on the protein transducin by loading it with the small molecule guanosine triphosphate (GTP). When bound to GTP, transducin turns on a phosphodiesterase, an enzyme that breaks down cyclic guanosine monophosphate (cGMP � another small molecule). High concentrations of cGMP open specialized ion channels in the outer cell membrane. Thus, by reducing the concentration of cGMP, light changes the flow of ions across the membrane of photoreceptive neurons, producing an electrical signal that is necessary for communicating with the brain. (Emphasis added in quotes.)Now that’s just to turn the signal on. When the light stops, it needs to be turned off quickly. Normally, it would take too long for this process to reverse, but the retina has a standard procedure that takes care of it:But this presents a problem. Photoreceptor cells can turn off in less than a second in response to a brief flash of light. In contrast, the hydrolysis of GTP by transducin requires tens of seconds to complete, making it difficult to understand how such a mechanism could account for the rapid turn-off of photoreceptor cells. To get around this problem, photoreceptor cells possess a protein called regulator of G-protein signalling 9 (RGS9) that accelerates transducin’s ability to hydrolyse GTP.Blumer describes what happens when a person has a defect in this accelerator protein. It can take tens of seconds to adjust to a bright room when walking out of a theater. It can take tens of seconds to see when driving into a dark tunnel. And perhaps the worst of all (for Rose Bowl fans): “Moreover, people with this problem also suffer from difficulties in seeing certain moving objects (such as balls thrown during a sporting event).” Having one such accelerator protein would be amazing enough, but now – the rest of the story: “RGS9 is one of nearly 30 such RGS proteins, which regulate signalling by hundreds of receptors coupled to transducin-like G proteins in cell networks of the nervous, cardiovascular, sensory and immune systems.”Kendall J. Blumer, “Vision: the need for speed,” Nature 427, 20 – 21 (01 January 2004); doi:10.1038/427020a.We need to know things like this to avoid taking our bodies for granted. This one deserves a little pondering. Do some simple experiments; see how quickly your eye adjusts to different light levels, and think about all those little protein machines knowing just what to do on cue. Poor Charlie. The eye as he knew it was enough to give him cold shudders. In 1859, biochemistry was not even a science yet. Charlie must be approaching absolute zero by now. A book preceding The Origin of Species by about 2900 years, by a wiser man (Solomon), makes a lot more sense after reading the above description: “The hearing ear and the seeing eye, The LORD has made them both” (Proverbs 20:12).(Visited 13 times, 1 visits today)FacebookTwitterPinterestSave分享0
Science Daily asked, “Could salt crusts be key ingredient in cooking up prebiotic molecules?” What if the answer is “No”? Just asking the question must be newsworthy. It invokes the power of suggestion. Stefan Fox told members of the European Planetary Science Congress last week that his team cooked up a new idea about the origin of life. First, they imagined what the ocean chemistry might have been like 3.8 billion years ago. Then they added salt to their imagined seawater recipe. After performing experiments “evaporating solutions of artificial primordial seawater and then baking the salty residue in an atmosphere of nitrogen and carbon dioxide to volcanic temperatures of 350 degrees Celsius,” they found pyrrholes – molecules that can be found in heme and chlorophyll. The salt crusts bind to amino acids and stabilize them against evaporation, they said. So what? These molecules are not alive in any sense of the word. “Our aim is to identify types of small molecules that might have participated in a hypothetical next step of chemical evolution,” they said. So far they got some simple amino acids, peptides and pyrrholes. (Presumably the amino acids came from Miller-style lightning discharges or from comets, and were in very small concentrations – but Fox said there were hundreds of thousands of years in which they could have accumulated.) The astrobiologists at the conference were probably happy to hear about a new way to keep amino acids from being rapidly destroyed. “A clear chemical pathway for the development of the raw materials of life would add support to the theory of life evolving beyond Earth,” the article ended.Allowing storytellers into the science lab (12/22/2003 commentary) was a crime against humanity. It permitted all kinds of mischief to be tolerated in the name of science. Fox (who should stop following in the footsteps of the previous Fox, Sidney Fox, in mythmaking, but should watch Fox News instead), is apparently unaware that salt is the last thing you want around to cook up life (06/25/2009). But in the new Darwin Storytelling Contest view of science, anything that lends itself to bottom-up thinking (hydrogen to people) is considered progress. No matter the illogic and contradictions, these liars will take their amino acids with toxic salt if they have to. They need those building blocks of lie (03/19/2008).(Visited 5 times, 1 visits today)FacebookTwitterPinterestSave分享0
dana oshiro Tags:#start#startups A Web Developer’s New Best Friend is the AI Wai… With almost half a million broadcasters, popular lifecasting service Justin.TV could probably create a section for clown fightclubs and still have thousands of video voyeurs clamoring to entertain us. The company just launched its first in what is likely to be a long list of sub-sites. Gaming.justin.tv is a sub-site that offers viewers info, events and videos specific to the gaming community. The company is already working on followup sites with music and social channel queued up for the future. It’s hard to believe that a young man and his hat camera could build an empire like Justin.TV. In just three years the company has gone from a four-person gritty apartment startup, to a service with more than 21 million unique monthly visitors. The site currently serves the equivalent of 16,946 standard DVDs per hour in video content and ReadWriteWeb featured it as one of the top 5 video sites in the world. With the new channel sub-sites, this empire is about to expand even further. In a blog post the company writes, “Justin.tv sub-sites will have their own promoted content and could include custom features as well…Now that there’s a dedicated gaming area, we’re free to build new features just for gamers that may not have been possible before.”Last month ReadWriteWeb covered Wikia’s profit announcement. Wikia acknowledged that corporate sponsorships on sites like the World of Warcraft and Halo communities were particularly lucrative. Justin.TV is likely to see even more advertiser interest. Video production often requires much more time than the average wiki contribution, and viral video makers are perhaps some of the most sought after customers due to their far-reaching networks. If corporations can get to a sub-site’s influencers and gain favorable reviews, then the outreach could generate huge sales growth. Furthermore, given the fact that the Justin.TV’s traffic more than doubles Wikia’s, it will be hard for advertisers to resist the lure of these fan communities. To check out the first sub-site, visit gaming.justin.tv. 8 Best WordPress Hosting Solutions on the Market Related Posts Why Tech Companies Need Simpler Terms of Servic… Top Reasons to Go With Managed WordPress Hosting
From high-speed car chases to luxury car commercials, camera cars are secretly driving alongside capturing all the action.Cover Image via Camera Car IndustriesCamera cars come in all shapes and sizes. They are classified as self-propelled vehicles engineered for mounting and manning cameras and equipment. They are often painted or wrapped in a matte black finish, so they don’t reflect light while shooting.Their history goes all the way back to the first mass-produced vehicles. In this photo from the 1925 film Ben-Hur: A Tale of the Christ, a camera car prepares to film the chariot race sequence.Image via Iverson Movie RanchBy the 1930s, picture cars (the cars that are on camera) were commonly placed in front of rear-projection screens. That technique of process photography has been adapted and is still used today, but with green screens. Action films of the 1940s and 1950s started using cameras on and inside moving vehicles, and by the 1960s we would see the beginning of the modern camera car.Insert CarImage via Elliot Location EquipmentThe insert car (which is actually almost always a truck or van) is a vehicle with a series of platforms that hold a camera crew and their equipment. It is a camera crew’s fully functioning mobile set.It allows an array of different camera and lighting setups, like plate-shots or crane-shots. The insert car also has an on-board generator used to power any camera equipment or light kits. Typically, the film’s director is sitting inside the cab watching footage, while camera operators stand on the platforms filming.The insert car can be driven in front of, behind, or to the side of a picture car. Most frequently they are used to tow picture cars. They are also used to film establishing shots, often just driving through city streets.Process TrailerImage via Moving PicsThe process trailer is a low rise platform that holds a picture car. The trailer moves along roadways, allowing the camera crew to film a natural-looking car movement. They can also be referred to as an insert trailer or a low loader.These are frequently used if no other vehicles will be visible near the picture car. If other vehicles pass by, the height difference will make it apparent that the picture car is on a trailer.Most insert cars can tow the process trailer with a rear trailer hitch. However, there are some insert cars that can also side-tow the process trailer, allowing filmmakers to have camera in front and beside a picture car simultaneously.Image via Camera CarsTow DollyImage via Camera CarsA tow dolly is a specialty trailer that only holds the front tires of a picture car. (These are the types of trailers you frequently see movers using, like U-Haul.)These are usually used when the camera crew is relying on car-mounted rigs, rather than standing beside the vehicle. They also offer a more natural look when driving through traffic, as there isn’t much of a height difference next to other cars on the road.If pulled by an insert car, the most common setup is a camera on the insert car facing the picture car straight on while an additional camera is mounted to the side of the vehicle.Camera Car – Sport Utility Vehicles (SUV)Image via Pursuit SystemsSUV camera cars have become the most well known among people outside of the industry. These camera cars are flashy, usually a modified Porsche Cayenne or Mercedes-Benz ML55 AMG.These high-end SUVs are not only chosen because of their looks, they can seat five crew members and are built for speed. They also feature a solid braking system, which allows them to keep up with high-speed shots and then stop on a dime. Camera Car – CarsImage via Pursuit SystemsThough the SUV has become the most well-known camera car, there are still plenty of camera “cars” used on set. Camera cars are used for high-speed chases or close-up follow shots of vehicles.The Mini Cooper featured above was specifically designed for the Fast & Furious franchise. It was used to film the races inside of parking garages.Camera Car – CustomImage via House of PropsJust like the world of custom cars, there are plenty of custom camera cars as well. Many companies build original vehicles for specific films. One of the most popular is the Go Mobile.Go Mobile is a flat vehicle that allows a film to use any type of vehicle body. The above feature taxi frame can be replaced, and another body type put it its place.Image via Aint It Cool NewsAnother custom vehicle was the one above, built for Children of Men to capture the incredible long take. The custom camera car actually has two drivers, depending on which direction the vehicle is moving. Camera Car – CartsImage via Telescopic Camera CranesCamera cars are not always the fastest or most powerful vehicles. Often times a production may need a silent vehicle or a low-impact cart. These carts can be either gas or electric.By “low impact” we are referring to a vehicle that will not damage a surface, much like in the above photo. The camera car used on the field will not damage the playing surface, whereas a car or truck could weigh it down and leave tire tracks.Interested in more production posts like these? Let us know in the comments below.
Parupalli KashyapIndia were knocked out of badminton semi-finals 0-3 by England, who will now play for gold against Malaysia, who struggled their way past Singapore 3-2 at the Commonwealth Games here.England had to fight hard for their 3-0 victory, particularly in the mixed and men’s doubles. India’s top singles player Parupalli Kashyap lost his match against Rajiv Ouseph in straight games at the Emirates Arena on Sunday.Chris Adcock was England’s star performer, having a fair share in winning both the doubles. He first won the mixed double with wife Gabriel and then paired up with Andrew Ellis to take the men’s doubles, both matches going into decisive third game.The Adcocks looked like running away with their match when they took the first game 21-16 and led 15-8 in the second against Jwala Gutta and Akshay Dewalkar. But the Indians fought back to take 12 of the next 13 points to force a decider.Kashyap was up against a fighting Ouseph, who had a tougher second game but pulled it off 21-16, 21-19.Adcock was back on court, this time for the men’s doubles with Ellis against Dewalkar and Pranaav Chopra.The Indians took the first game 21-12 but Adcock and Ellis rallied brilliantly to take the second at 13, one particular rally going to 82 strokes. The English partners steadied themselves to take the decider 21-16.England have not lost a match in the competition.Ouseph was the only English player who played at the New Delhi Games four years ago and thinks his team can beat defending champions Malaysia.advertisementMalaysia had to go all the way to overcome Singapore 3-2.Mixed doubles pair Chan Peng Soon and Lai Pei Jing had to come from behind to edge out Danny Chrisnanta and Vanessa Neo 17-21, 21-12, 21-14 in a thriller for the winning point.Men’s doubles pair Tan Wee Kiong and Goh V Shem put Malaysia ahead beating Danny Chrisnanta and Chayut Triyachart 21-17, 18-21, 21-16 but Singapore levelled the score when Xiayou Liang beat Tee Jing Yi in straight sets, 21-12, 22-20.Chong Wei Feng, who came in for injured Lee Chong Wei as the top men’s singles player, restored Malaysia’s lead by beating Derek Wong, 21-9, 21-18.However, Singapore levelled yet again when their women’s doubles pair Shinta Mulia Sari and Lei Yao beat Woon Khe Wei and Vivian Hoo 9-21, 18-21.Eventually, it was left Peng Soon and Pei Jing to eke out the decisive victory.