Jumping spider uses fuzzy eyesight to judge distance

first_imgAnterior view of the jumping spider, Hasarius adansoni. A pair of principal eyes is located at the anteromedial area of the body, lying between two lateral eyes. Image © Science/AAAS (PhysOrg.com) — One of the ways in which humans determine distance is by estimating the sharpness of an image—closer objects produce a sharp image, while those further away are out of focus. For us, this is a minor additional method of judging distance, but now scientists in Japan have for the first time found an animal that appears to use this method as its primary means of depth perception. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Adanson’s jumping spider (Hasarius adansoni) captures prey by jumping from a distance. The question that has puzzled scientists is, how do their eyes allow them to perceive depth? Their front eyes do not give them the two distinct but overlapping views needed for binocular vision, used by humans. They also do not use the motion parallax many insects use, since their head remains motionless when they are about to jump. (Motion parallax is a system in which the animal moves its head from side to side so that close objects move further across the field of view than those further away.) Now the new study reveals that the spiders use an image defocus system to enable them to judge distances.Adanson’s jumping spider has excellent eyesight, provided by eight eyes: a pair of primary eyes (large and at the front), two anterior lateral eyes, one at either side of the primary eyes and also facing forward, and two smaller pairs of eyes on the top of their heads, one of which is almost undetectable by the naked eye. The research team, led by Takashi Nagata, from Osaka City University, blocked the anterior lateral pair of eyes of the jumping spider and found that they use this smaller pair of eyes to detect motion, but blocking their vision had no effect on the spider’s ability to judge distance.It has been known since the 1980s that the retinas in the principal eyes in jumping spiders have a unique structure that is shaped like a staircase, and they contain four layers of photoreceptors rather than one layer, as human eyes have. The new study revealed that the two deeper retinal layers contain pigments sensitive to green light and the two layers closest to the surface contain pigments sensitive to ultraviolet light. Of the two layers most sensitive to green light, only the deepest receives focused images, and the other receives an out of focus image.To test the idea that the spiders could judge depth from the amount of defocus in the second green pigment layer, the researchers placed spiders one at a time in a container, along with some fruit flies and then tested their ability to catch the flies under red and green lights. The results showed that green light was necessary for accuracy since the spiders were able to judge their jumps successfully in green light, but often misjudged in red light (which does not contain the shorter wavelength green light). The researchers also created a mathematical model to predict how far off the jumps would be under different wavelengths of light, and found that the model did accurately predict the spiders’ performance.The researchers concluded that the spiders were indeed using the extent of defocus in the second green pigment layer of the retina to judge distance, and they are the only known animals to use this system as their primary means of depth perception. Since other jumping spiders have the same type of retina, they may also use the same method.In a paper published in the journal Science, the researchers conclude that further study of the vision system used by jumping spiders is necessary and that it could have applications in robotic and other computer vision systems. © 2011 PhysOrg.com Citation: Jumping spider uses fuzzy eyesight to judge distance (2012, January 27) retrieved 18 August 2019 from https://phys.org/news/2012-01-spider-fuzzy-eyesight-distance.html Explore further More information: Depth Perception from Image Defocus in a Jumping Spider, Science 27 January 2012: Vol. 335 no. 6067 pp. 469-471. DOI:10.1126/science.1211667ABSTRACTThe principal eyes of jumping spiders have a unique retina with four tiered photoreceptor layers, on each of which light of different wavelengths is focused by a lens with appreciable chromatic aberration. We found that all photoreceptors in both the deepest and second-deepest layers contain a green-sensitive visual pigment, although green light is only focused on the deepest layer. This mismatch indicates that the second-deepest layer always receives defocused images, which contain depth information of the scene in optical theory. Behavioral experiments revealed that depth perception in the spider was affected by the wavelength of the illuminating light, which affects the amount of defocus in the images resulting from chromatic aberration. Therefore, we propose a depth perception mechanism based on how much the retinal image is defocused. The eyes have it for perfect predatorlast_img read more

Arizona solar plant achieves six hours after sun goes down

first_img Citation: Arizona solar plant achieves six hours after sun goes down (2013, October 11) retrieved 18 August 2019 from https://phys.org/news/2013-10-arizona-solar-hours-sun.html More information: www.aps.com/en/ourcompany/news … r-sun-goes-down.aspx © 2013 Phys.org Explore further Solana is one of the largest power plants of its kind in the world. Beyond size, what makes Solana special as a solar power plant is the ability to store the heat from the sun for electrical production at night, using substantial thermal storage to keep the juice flowing for hours after sundown. In a report on the Arizona plant by IEEE Spectrum, the point was made that proving that this storage tech can work is a huge step for the solar industry. Intermittency, said the report, is still among the most common complaints about industrial-scale renewable energy.According to Abengoa, “Solana’s thermal storage system, without the use of the solar field, can produce clean energy for six hours at maximum power.” These six hours, said the company, can satisfy Arizona’s peak electricity demands during summer evenings and early night hours. Abendgoa added that “Dispatchability also eliminates intermittency issues that other renewables, such as wind and photovoltaics, contend with, providing stability to the grid and thus increasing the value of the energy generated by CSP.”Abengoa is an international technology and engineering company, which began construction of the plant in 2010. A power purchase agreement with Arizona’s biggest electricity utility, Arizona Public Service, is in place covering the full solar plant’s output for its customers. Electricity generated by the plant at its peak would power around 70,000 homes. IEEE Spectrum refers to Gila Bend, Arizona, as a “solar power wonderland,” with four solar plants approved in the area. Don Brandt, APS President and Chief Executive Officer, said he regarded Solana as providing a boost toward the APS goal of making Arizona “the solar capital” of America. With the addition of Solana, APS will have 750 megawatts of solar power on its system by the end of the year, enough to serve 185,000 Arizona customers. Ivanpah solar plant in California starts energy feed to grid (Phys.org) —Abengoa’s Solana plant in the desert near Gila Bend, Arizona, passed commercial testing this week The 280-megawatt Solana solar thermal power plant producing electricity without direct sunlight made the announcement on Wednesday. Abengoa said Wednesday that the facility, about 70 miles southwest of Phoenix, can store the sun’s power for six hours via thermal energy. The three -square-mile facility near Gila Bend uses concentrated solar power (CSP) technology to collect the sun’s heat. Thermal energy storage is Solana’s distinctive feature. At 280 megawatts, Solana is one of the largest plants using parabolic mirrors. Its 2,700 parabolic trough mirrors follow the sun to focus heat on a pipe containing a heat transfer fluid, which is a synthetic oil. The heat transfer fluid flows to steam boilers, where it heats water to create steam. The steam drives 140-megawatt turbines to produce electricity. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Rs firms up by 18p to 6143 against

first_imgThe Indian rupee ended higher by 18 paise to 61.43 against the American currency after the long weekend holidays on sustained selling of dollars by banks and exporters.The rupee resumed higher at 61.41 per dollar as against the last Wednesday’s closing level of 61.61 per dollar at the Interbank Foreign Exchange (Forex) Market and hovered in a range of 61.3025 per dollar and 61.4700 per dollar before finishing at 61.43 per dollar, showing a rise of 18 paise or 0.29 per cent.Pramit Brahmbhatt, Veracity Group CEO said,’ the rupee appreciated to 61.3025, taking cues from the dollar which is at present is trying to recover from Monday’s fall in the global market. Investors preferred to book profit in the already elevated dollar’.last_img

Costa Rican striker Yendrick Ruiz joins FC Pune City

first_imgThe 28year old brother of Costa Rican legend Brian Ruiz, is the star striker for Club Sport Herediano which plays in the Primera Divisi?n de Costa Rica, the top tier of the Costa Rican football league system.Yendrick began his career in the Liga Deportiva Alajuelense, where he formed part of the minor leagues since 2003. He made his official debut in First Division with Alajuelense He also represented Puntarenas Football Club in 2010, where he obtained the sum of 13 goals in 36 games. Also Read – Khel Ratna for Deepa and Bajrang, Arjuna for JadejaIn 2012 he joined Club Sport Herediano where he has raised his reputation of being an intelligent player with lethal goal scoring abilities. In the last 3 years at Herediano, he has scored an impressive 43 goals in 100 games, his last season being his most impressive one where he was lethal upfront for his team scoring 23 goals and assisting in another 12 goals for his team.Gaurav Modwel, CEO FC Pune City said, “After having a successful auction where we got the players we needed, we have gathered steam with regards to foreign player signings. We are very happy to announce the signing of Yendrick Ruiz, a talented striker from Costa Rica. Also Read – Endeavour is to facilitate smooth transition: Shastri”Yendrick is an intelligent player with good eye for goal and his reading of the game is excellent. He has been on a goal scoring spree in last couple of seasons for CS Herediano. He will surely be an asset to the club and a star for the Pune City fans.” Coach of FC Pune City, David Platt said, “Yendrick’s reading of the game and his skill in front of the goal will certainly be an asset to the team. Yendrick is a proven goal scorer and we are hoping his addition to the team bundled with his overall technical ability will make our attack line a force to reckon with.”Expressing his joy on joining FC Pune City, Yendrick Ruiz said, “The seriousness of the (FC Pune City) management for having me onboard and part of club was one of the primary reasons for me to join FC Pune City. This will certanly be one of the biggest challenges of my career sofar and I look forward to this challenge.last_img read more

An unconventional Mothers day celebration at old age home

first_imgSenco Gold & Diamonds, the largest jewellery retail chain from Eastern India, celebrated this Mother’s Day with a difference, by spreading happiness in the lives of residents of Sanjivani old age home in Raipur. The officials of Senco Gold & Diamonds visited the old age home to spend time with the residents, and celebrated the day by cutting cake and organizing various fun-filled activities. It was an emotional occasion for the elderly women at the old age home who were extremely touched by the gesture and responded with joy and enthusiasm. Also Read – Add new books to your shelfSpeaking about the initiative, Shaankar Sen, Managing Director, Senco Gold & Diamonds, said, ‘At Senco Gold & Diamonds, we keep doing small and big initiatives for a larger social cause. It was a humbling experience to see how little things make a huge difference to the residents of Sanjivani old age home in Raipur. The activity has instilled a commitment within us to conduct such programmes more often to make a meaningful contribution towards the society.” Also Read – Over 2 hours screen time daily will make your kids impulsiveSenco Gold & Diamonds, founded in the year 1938 by late MC Sen is one of the oldest jewellery organizations in India. Headquartered in Kolkata, Senco Gold & Diamonds has 89 stores spread across India and is the largest jewellery retail chain from Eastern India. Senco Gold & Diamonds has an array of products on offer for every occasion, with more than 10,000 new designs being developed every year. Their popular Everlite Collection has exquisitely designed light-weight jewellery available at extremely affordable prices. Senco Gold & Diamonds exports to countries like USA, UK, Singapore and Middle East.last_img read more

Voters may experience stifling heat and humidity on May 19

first_imgKolkata: Rains accompanied with thunderstorm will lash some of the south Bengal districts till Friday following which the temperature will continue to rise, the Regional Meteorological Centre in Alipore predicted.The weather office said the last phase of election in the state will be conducted amidst hot and humid condition as the mercury is expected to soar from the next Saturday. “The thundershower will take place in various South Bengal districts in the next 48 hours. There is a possibility of lightning in South Bengal districts. A gusty wind of around 40-50 km per hour speed along with rain will hit West Midnapore, East Midnapore, Jhargram districts,” a senior official of the MeT office said. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataPeople in the city and other districts had been under a tremendous heat spell for the past few days. They heaved a sigh of relief after rain and thundershower hit various South Bengal districts in the evening of May 13. People from the districts such as Birbhum, Nadia, Bankura and Malda witnessed moderate to heavy rainfall along with gusty wind on repeated occasions since Monday. It can be mentioned here that the temperature touched 42 to 43 degree Celsius in the Western districts such as Bankura, Purulia and West Midnapore. Many other districts of South Bengal also had been under tremendous heat spell. Also Read – Lightning kills 8, injures 16 in stateThe temperature in the region remained high throughout the day due to the inflow of northwesterly wind to the state from the neighbouring states. There has been little moisture incursion into Gangetic Bengal and thereby preventing the formation of a storm-triggering system. A Nor’wester brought the recent heat spell under the control. A thundershower triggered by Nor’wester lashed North 24-Parganas, Hooghly Howrah and adjoining parts of the city late on Monday night. The mercury dipped by a few notches bringing temporary respite to the people. The discomfort level may again shoot up as the humidity is expected to be on the higher side from next Saturday. Various North Bengal districts may however witness hailstorm and thundershower in the next couple of days. A prediction of hailstorm poses a concern for the team garden owners as it may damage the tea production in various North Bengal districts.last_img read more

Noted poets to be conferred with Mystic Kalinga Literary Award

first_imgTo celebrate the creative spirit of Bhubaneswar and commemorate the literary diversity it offers, Odisha Diary Foundation (ODF) and Odisha Media Info Service (OMIS) Private Ltd organise annual Mystic Kalinga Literary Festival (KLF) every year, bringing together best minds in the world of literature within and outside of Odisha and India.This festival of verse, music, dance, and discussion dedicated this year to the concept of Bhakti and will be held in Bhubaneswar and Chilka from January 5 -7, 2019 Also Read – Add new books to your shelfNoted poet Ashok Vajpeyi and Harihar Mishra will be conferred with prestigious Mystic Kalinga Literary Awards this year. This was informed by the Mystic Kalinga Festival, Director, Rashmi Ranjan Parida. The award has been instituted to recognise and celebrate three prolific writers, poets, and performers in Odia, in one Indian language, and in one international language. The awardees have been chosen keeping in mind their contribution to their specific language and genres. The awards will be announced on January 3, 2019. Also Read – Over 2 hours screen time daily will make your kids impulsiveAshok Vajpeyi is a noted Hindi poet, critic, essayist and translator, and a dynamic presence in the Indian cultural scene. He is the author of thirty-eight books of poetry and criticism in Hindi and the founder/editor of eight journals in Hindi and English. He is the recipient of the Sahitya Akademi Award (1994) for his book Kahin Nahin Vahin. Harihar Mishra is known for his versatility as a dramatist as well as the writer of prose and poetry. As a dramatist, he has worked on major works such as Chilika Tire for the radio and among his famous poetry books – Dibya Asantosh stands tall. He had won the Odisha Sahitya Akademi Award way back in 1977 for his drama Ratira Duiti Dena. Prateek Pattanaik will also be felicitated with the Mystic Kalinga Literary Award (Special Citation) during the festival. Prateek Pattanaik is a young researcher of Odia literature and Odissi music. Prateek’s work consists of several projects to create digital documentation of vulnerable cultural practices including performing arts, musical traditions, lesser known monuments, neglected languages, and palm leaf manuscripts. Apart from that, Prateek research and write about Odisha’s ancient culture on the lines of mythology, the arts, and ethnomusicology. It should be noted that for the last three years Mystic Kalinga Festival has set a global benchmark in literary festivals. This year more than 100 celebrities from the world of literature, music, cinema, dance, the theatre will assemble in the temple city of Odisha to deliberate on the theme of ‘From the Carnal to the Cosmic: A Celebration of Bhakti Poetry’. Eminent writers and Odisha’s living legends like Sitakant Mahapatra, Ramakanta Rath, Pratibha Ray, and others will join the festival as guests of honour and speakers. Renowned writer Hindi poet and critic Ashok Vajpeyi will be the keynote speaker of the event and several Sahitya Akademi and Padma Awardees will be joining to discuss how literature transcends boundaries of artificial human creations and emotions. “Mystic Kalinga Festival is a celebration of bhakti. In a festival that is both celebratory and exploratory, the aim is not merely to discuss bhakti, but to distill its very essence. And hence we will see the remarkable diversity of modes and styles at this festival. Poets, dancers, storytellers, and musicians are as integral to this unique event as scholars and academics”, said Mystic Kalinga Festival, creative director, Arundhathi Subramaniam. Mystic Kalinga Festival – Director and Founder, Rashmi Ranjan Parida said, “Literature has the potential to connect a divided society and it can transform self-centeredness to world-centeredness. Kalinga Literature Festival was first launched in 2014 to celebrate this potential of literature. Mystic Kalinga Festival, an international festival of poetry and performances, emerged out of the need to connect to people’s hearts through poems, songs, dances, performances, and meditations”.last_img read more