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SAN FRANCISCO Solde Nike Air Presto Uncaged Ultra Verte , July 17 (Xinhua) -- U.S. researchers have found that while octopuses, squid and other cephalopods are colorblind, their weirdly shaped pupils may allow them to detect color and mimic the colors of their background.

The researchers, a fatherson team from the University of California, Berkeley, and Harvard University Solde Homme Nike Air Presto Uncaged Ultra Blanche Grise , believe that the key for cephalopods to be able to see color, just differently from any other animal, is an unusual pupil that allows light to enter the eye through the lens from many directions, rather than just straight into the retina.

The U-shaped, W-shaped or dumbbell-shaped pupil accentuates the chromatic aberration, and may enable cephalopods to judge color by bringing specific wavelengths to a focus on the retina Solde Nike Air Presto Uncaged Ultra Blanche , much the way animals like chameleons judge distance by using relative focus, said UC Berkeley graduate student Alexander Stubbs. They focus these wavelengths by changing the depth of their eyeball, altering the distance between the lens and the retina, and moving the pupil around to change its off-axis location and thus the amount of chromatic blur.

"We propose that these creatures might exploit a ubiquitous source of image degradation in animal eyes, turning a bug into a feature," Stubbs was quoted as saying by a UC Berkeley news release. "While most organisms evolve ways to minimize this effect Solde Nike Air Presto Uncaged Ultra Noir , the U-shaped pupils of octopus and their squid and cuttlefish relatives actually maximize this imperfection in their visual system while minimizing other sources of image error, blurring their view of the world but in a color-dependent way and opening the possibility for them to obtain color information."

Alexander Stubbs teamed up with his father, Harvard astrophysicist Christopher Stubbs, to develop a computer simulation to model how cephalopod eyes might use this to sense color and published their hypothesis online in the journal Proceedings of the National Academy of Sciences.

The two researchers concluded that a U-shaped pupil like that of squid and cuttlefish would allow the animals to determine the color based on whether or not it was focused on its retina. The dumbbell-shaped pupils of many octopuses work similarly, since they are wrapped around the eyeball in a U shape and produce a similar effect when looking down.

"Their vision is blurry, but the blurriness depends on the color Solde Homme Nike Air Presto High Noir ," Stubbs said. "They would be comparatively bad at resolving white objects, which reflect all wavelengths of light. But they could fairly precisely focus on objects that are purer colors, like yellow or blue, which are common on coral reefs and rocks and algae. It seems they pay a steep price for their pupil shape but may be willing to live with reduced visual acuity to maintain chromatically-dependent blurring, and this might allow color vision in these organisms."

"We carried out extensive computer modeling of the optical system of these animals, and were surprised at how strongly image contrast depends on color Solde Homme Nike Air Presto Safari Noir Jaune ," said Harvard's Stubbs. "It would be a shame if nature didn't take advantage of this."

Human and other mammalian eyes have round pupils that contract to pinholes to give us sharp vision, with all colors focused on the same spot. But as anyone who's been to the eye doctor knows, dilated pupils not only make everything blurry, but create colorful fringes around objects, what is known as chromatic aberration. This is because the transparent lens of the eye, which in humans changes shape to focus light on the retina Solde Femme Nike Air Presto BR Rose , acts like a prism and splits white light into its component colors. The larger the pupillary area through which light enters, the more the colors are spread out. The smaller our pupil, the less the chromatic aberration.

"We believe we have found an elegant mechanism that could allow these cephalopods to determine the color of their surroundings, despite having a single visual pigment in their retina," said the younger Stubbs. "This is an entirely different scheme than the multi-color visual pigments that are common in humans and many other animals. We hope this study will spur additional behavioral experiments by the cephalopod community."

by Justice Lee Adoboe

ACCRA, Jan. 17 (Xinhua) -- Fifty-year-old Gabriel Agbeve joined China Harbor Engineering Company (CHEC) in July 2016 as a mason after the Chinese firm won the contract to carry out Ghana's port expansion project at Tema Solde Nike Air Presto Qs Verte , about 40km east of the capital Accra.

Due to his hard work, Agbeve was elevated by managers at CHEC to the position of Masons Foreman. He has since then been sent outside the country for further training to improve his skills.

"As they saw my performance, they took me outside the country to learn the casing so now I am also training the other masons in casing. We have some other guys who were unskilled laborers but the Chinese have trained them to be professionals," Agbeve told Xinhua during a working tour at Tema Harbor early this week.

Not only has he improved his skills, Agbeve is also able to provide for his family sufficiently, including his daughter now in the university from the wages he earns from his job at the Chinese firm.

"This company is the best because I have worked in about four or five companies before. I cannot mention their names here but I have progressed here far more than I did with the previous companies Solde Nike Air Presto SE Woven Bleu ," he said.

CHEC commenced the expansion work on the Tema Harbor in July 2016 and is expected to complete it within 51 months. The company has put in place procurement and employment measures that create a win-win situation for both employers and employees, as well as service providers and sub-contractors.

Even before half of the duration for the 1.5-billion-U.S. dollar contract elapses, many Ghanaians and companies have enjoyed transformational benefits and opportunities.

The 1,000 Ghanaians employed by the company, accord. Cheap NFL Jerseys Cheap NCAA Jerseys From China Cheap MLB Jerseys China Cheap Soccer Shirts Free Shipping Cheap NHL Shirts China Cheap NBA Hats China Cheap MLB Jerseys Free Shipping Wholesale Hoodies Wholesale Hats Wholesale NFL Hoodies