first_imgDay Two was moving day at the NSWTA State Cup with Men’s and Women’s scrambling for the all important finals positions.In the Men’s Open, Wests have swept before them with five wins from five games. Coach Tony Trad is confident about this tournament but they will have to be on their best as they cross over and face the other teams from the Pool of Death.Penrith finished first in the other pool with a draw with Hornsby their only blemish. Time will tell if the young boys from the foot of the mountain can stand up on its biggest stage.Canterbury finished second and like a good horse is well position to make a sprint for the post. They seem set to met Wests in the semi-final which will be an epic game. Hornsby finished third and will have to beat Easts to progress to the semi-finals where they are likely to face Penrith. In the Women’s, Easts have come through the heavy preliminary workload in the best position. Wollongong have been in good form but it should be another year before they make the final with Easts favoured to meet Canterbury in the big onme who play Wests in the other semi.Further results can be found from the NSWTA State Cup website – http://www.sportingpulse.com/assoc_page.cgi?assoc=856&pID=14last_img read more

first_imgAbout the authorPaul VegasShare the loveHave your say Liverpool goalscorer Van Dijk: I’ll take clean sheet over goalby Paul Vegas10 months agoSend to a friendShare the loveLiverpool defender Virgil van Dijk rates the clean sheet ahead of the goal he scored in victory at Wolves last night.om the Dutchman’s point of view, the three points and a shutout are the most important matters arising from another impressive result.“Not at all – I’m more happy that I’m keeping clean sheets with my team and winning games,” Van Dijk told Liverpoolfc.com, when asked if he was frustrated to have gone nearly 12 months without scoring for his club.“Obviously scoring a goal is a bonus and obviously a very proud moment and hopefully there’s more to come, but I’m more focused on winning games.“We are very happy and at the end I am happy with the win. In the first half we were a bit sloppy at times, but second half we did it well and we are very happy that we won.“It’s a very tough place to come with these circumstances and how they play. They have shown throughout the season they are very good and disciplined and they have a clear idea. We knew before and it’s how we reacted to it and in the second half we dominated and created good chances.” last_img read more

first_imgSouth Korean shipping company Hyundai Merchant Marine (HMM) has extended the term of its Chief Executive Officer (CEO) C.K. Yoo. until 2021.“All employees of HMM – with a sense of great duty and mission as the only national ocean carrier – will give our all to leap forward as one of the top global shipping carriers.”  “We believe that HMM will gain great cost-competitiveness and strengthen its sales power,” Yoo said.The term extension is being reported in the light of the company’s 42nd regular shareholders’ meeting held at the HMM’s headquarters in Seoul.Yoo is expected to resume the company’s fleet renewal campaign which has seen HMM order construction of five very large crude carriers (VLCC) last year at DSME and acquire two 11,000 TEU containerships.Earlier this week, the company announced it had secured USD 420 million to finance the construction of the quartet.As announced by Yoo in January, the company intends to double its vessel capacity by 2022.As part of the plan, HMM revealed an investment in the construction of 22,000 TEU newbuilding that is expected to be formalized shortly.Furthermore, the company has launched a digitalization of its operation via a switch to a Cloud-based next-generation system, planned to be completed by 2020.Image Courtesy: HMMlast_img read more

first_imgReaction has been pouring in on social media following a mass shooting late Sunday night where two people were killed and at least 12 others were injured in Toronto’s Greektown neighbourhood.The shooting happened near Danforth and Logan Ave. just after 10 p.m.Toronto Police Chief Mark Saunders said early Monday that police arrived at the scene and quickly identified the suspect, who was armed with a handgun. An exchange of gunfire ensued, and Saunders said the 29-year-old shooter likely died of gunshot wounds. Advertisement Advertisement Many celebrities took to social media to react to the tragedy, with the hashtags #Danforth and #TorontoStrong.Canadian actor Patrick J. Adams wrote, “Another night of senseless loss and brutality in my home town.”Another night of senseless loss and brutality in my home town. Praying that some of these reported injuries from the shooting don’t turn into fatalities. Thank you to all the officers and doctors working hard tonight to deal with the aftermath. #danforth— Patrick J Adams (@halfadams) July 23, 2018Canadian actress Laura Vandervoort wrote, “Heart broken to hear about the #Danforth shooting this morning. My love and condolences to the victims and their families.”Another senseless shooting in my home town. Heart broken to hear about the #Danforth shooting this morning. My love and condolences to the victims and their families. Praying those injured are able to recover not only physically but emotionally. #toronto— Laura Vandervoort (@Vandiekins22) July 23, 2018Canadian actor Jay Baruchel wrote, “A few years ago I chose to move to the east end of Toronto, first to East York and then the beach. Every day I’ve been reminded why I made that choice. I truly love it here. What happened on the Danforth last night was ugly, opportunistic barbarism.”A few years ago I chose to move to the east end of Toronto, first to East York and then the beach. Every day I’ve been reminded why I made that choice. I truly love it here. What happened on the Danforth last night was ugly, opportunistic barbarism.Toronto can and will endure.— Jay Baruchel (@BaruchelNDG) July 23, 2018Canadian racing driver Robert Wickens wrote, “Something needs to change! My thoughts go out to all the victims.”Just got back to Indianapolis to read about what happened in Toronto tonight. Something needs to change! My thoughts go out to all the victims. Thank you to the emergency response staff for there hard work in trying to keep the fatality rate as low as possible tonight. #Danforth— Robert Wickens (@robertwickens) July 23, 2018Canadian former women’s ice hockey player Hayley Wickenheiser wrote, “Oh Toronto…  #Danforth.”Oh Toronto…??#Danforth— Hayley Wickenheiser (@wick_22) July 23, 2018Former Barenaked Ladies frontman wrote, “‘This is where we used to live.’ For 25 years. And it’s where my kids live. What an awful, violent year for Toronto. #Danforth.” Facebook LEAVE A REPLY Cancel replyLog in to leave a comment Advertisement Login/Register With: Twitterlast_img read more

first_imgThe French professional football league have announced that two more matches have been postponed due the ongoing civil unrest in FranceThis comes in light of protests and demonstrations going havoc due to president Emmanuel Macron’s eco-tax policy on fuel.The riots, which have mainly occurred in Paris, have now become a major issue for the police with several sporting events having been impacted on as a result.PSG, Neymar, Ligue 1PSG ultras sent a warning letter to Neymar Manuel R. Medina – September 14, 2019 Brazilian superstar Neymar might play today his first game of the season for Paris Saint-Germain and the team’s ultras have warned him.The Ligue 1 website announced that Montpellier, who currently sit third in Ligue 1, had their match away to Nantes postponedPatrick Vieira’s Nice side’s game against Saint-Etienne on Friday is also being put on hold at the request of the local authorities.The likes of Paris Saint-Germain, Bordeaux, AS Monaco, Marseille and Lyon have all had fixtures rescheduled in light of the protests.last_img read more

first_imgThe resupply mission will blast off July 24. SpaceX SpaceX’s Falcon 9 static fire test has been completed, with the spacecraft eyeing a July 24 launch for a resupply mission to the International Space Station (ISS). The Dragon had previously visited the ISS in April 2015 and December 2017 for resupply missions.”Space Dragon flies thrice,” Elon Musk tweeted Friday afternoon, adding in response to another tweet that the Texas and Florida Starship prototypes will fly in two to three months.NASA also tweeted the news, saying the Dragon spacecraft will deliver supplies and cargo to the ISS. .@SpaceX is now targeting July 24 for the launch of the #Dragon spacecraft that will deliver supplies and cargo that will support dozens of the more than 250 science and research investigations happening aboard the @Space_Station https://t.co/BIPB5wAVGl— NASA (@NASA) July 19, 2019 SpaceX SpaceX pulls off dazzling Falcon 9 launch and landing in thick fog Elon Musk says his SpaceX Starship could go to the moon by 2021 SpaceX finds surprising cause behind Crew Dragon explosion SpaceX video highlights Crew Dragon parachute tests Meet the SpaceX Falcon Heavy, the world’s most powerful rocket 13 Photos Tagscenter_img Share your voice Sci-Tech Culture Post a comment Elon Musk’s SpaceX 0last_img read more

first_imgWikimedia Commons The Houston City Council unanimously approved Wednesday placing an item on the November 6 ballot that will present Houstonians with a choice to support or reject pay parity between police officers and firefighters.The ballot initiative would give firefighters a single-year pay raise of 25 percent, at a cost of $98 million a year.“And if by chance police, which are at the table right now asking for a pay raise, if they get one dime, that $98 million goes up,” said Mayor Sylvester Turner. The mayor, who opposes the pay parity amendment, said the city could not afford such an increase without gutting its workforce and city services. He said he will hold town hall meetings on the item in all the City Council districts before the election in order to make his point.District E Council Member Dave Martin echoed Turner’s message. He spoke directly to city employees other than firefighters. “A 25 percent salary increase has a dramatic effect on your pension, which we’ve worked the last two years to get under control,” Martin said.In a recent interview with Houston Matters, Turner argued that the pay parity the Houston Professional Fire Fighters Association (HPFFA) demands isn’t logical because the functionalities of the Police and Fire Departments are not the same.HPFFA President Patrick M. ‘Marty’ Lancton said in statement they are “grateful that the City Council members were led by their conscience and their ministerial duty, and not by political arm-twisting.” Share Xcenter_img Listen To embed this piece of audio in your site, please use this code: 00:00 /00:54last_img read more

first_imgBy Lenore T. Adkins, Special to the AFROThe political downfall and resurrection of the late Marion Barry, beloved by many as “Mayor for Life,” and derided by some as a crooked politician, figures prominently in a new special documenting the District’s 90s-era highs and lows.Washington in the ‘90s premieres 8 p.m. July 10 on WETA TV Channel 26 and HD. The hour-long program chronicles Washington, D.C.’s transition from a city of headline-grabbing violence and corruption to a land of opportunity. The AFRO received an advanced copy of the special for reporting purposes.Marion Barry (D.C. mayor, 1979-1991, 1995-1999) during his inauguration parade, January 1995Black Washington is on full display in the program. It dives into the go-go music scene.  In the ’90s, Go-Go was more popular in D.C. than Hip Hop. But many Go-Go clubs, including the Ibex, were shut down because of the shootings and other violence that many blamed on the music.The special also details former D.C. Mayor Sharon Pratt’s stumbles in office – she made the unpopular decision to scuttle Barry’s popular summer jobs program and was widely blamed for losing the Washington Redskins.The documentary showcases the Million Man March, the construction of the Green Line and the subsequent revitalization of U Street that included the reopening of the historic Lincoln Theater.Washington in the 90s deploys archival footage, music, and original interviews with Washingtonians to bring the 1990s to life. WETA Producer Seth Tillman, 37, who grew up in and around the District in the 1990s, created a program that amplifies what he thinks newcomers and Washingtonians should know about the city and why what happened back then is relevant today. “It seems almost like a simpler time right now, but there was a stronger D.C. identity and people feel that sometimes slipping away,” Tillman told the AFRO.Sharon Pratt (D.C. mayor, 1991-1995)Among those interviewed are Cora Masters Barry, former first lady of Washington, D.C.; former D.C. mayors Anthony Williams and Pratt; Kamal Ali, co-owner of Ben’s Chili Bowl; author and activist Tony Lewis Jr.; retired Washington Redskins player Darrell Green; filmmaker Sam Bardley; and NBC4 anchor Pat Lawson Muse. Long-time NBC4 anchor and reporter Doreen Gentzler narrates the program.Gentzler joined NBC4 in 1989 and had been on the job six months when federal and local authorities arrested Marion Barry in an undercover operation in a D.C. hotel room. Gentzler remembers her co-anchor Jim Vance was out at a dinner, so the responsibility of breaking the news – and interrupting the popular show LA Law – fell on her shoulders.“I just remember thinking, ‘I am not the right person to do this six months on the job. Let’s find Vance. He needs to do this or we need to do this together,’” Gentzler told the AFRO. “I don’t want to be right out there by myself with this one.”It was a tumultuous time in the District and Barry became a national punchline. The documentary shows grainy footage of the former mayor smoking crack with a woman who wasn’t his wife and David Letterman lampooning the former mayor on the comedian’s namesake late-night talk show.In a story of D.C. legend, the polarizing Barry launched his political comeback after serving six months in prison on a misdemeanor drug charge, winning the Ward 8 seat on the D.C. City Council in 1992. He was reelected mayor for his fourth and final term in 1994, defeating Pratt.In 1995, Congress launched the District of Columbia Financial Control Board to monitor city spending, in light of financial woes dogging the city. Two years later, Congress stripped Barry of the majority of his mayoral power, doling out nine crucial city departments to the control board. “It was painful to watch – that overseer federal government looming over us as if we were irresponsible people,” Pratt recalled in the documentary.The show credits Barry for bringing the MCI Center (then the home of the Washington Capitals) to the District, a move that helped spur downtown development and attracted restaurants and nightspots.Barry died in 2014 at the age of 78.Former Mayor Williams, then the city’s chief financial officer, took over after Barry decided not to run for reelection in 1998 and saved the city from financial ruin. Williams, a policy wonk, ushered in the city’s gentrification, spurring people to leave the suburbs and move into the city – a trend continuing today under Mayor Muriel Bowser.“The bad part of it is displacement where people who were part of the city had a stake in the city when the city was struggling,” Williams says in the documentary. “Now that the city’s doing well, they’re no longer a part of that picture.”The documentary’s light-hearted moments include the manufactured doomsday hysteria surrounding the imagined Y2K frenzy, the Washington Redskins winning the Super Bowl, and the blizzard of 1996. The Clinton years and the District’s emergence as a tech hub are included as well.last_img read more

first_imgThe birefringent dielectric metasurfaces were designed using silicon nanofins on top of a glass substrate. To achieve the desired phase shifts, 2-D parameter optimization was conducted using a rigorous coupled wave analysis (RCWA) method. The RCWA semi-analytical method is typically applied in computational electromagnetics to solve scattering from periodic dielectric structures. The length L and width W of the nanofin were in the range of 80 to 280 nm, height at 600 nm and period size P at 400 nm. The values were carefully selected to ensure the phase of the output light eliminated any undesired orders of diffraction. For the simulation, the nanofin was placed on a glass substrate and subjected to a fixed wavelength of incident light at 800 nm. Simulation results indicated the amplitude of transmission for most nanofins with diverse cross-sections were beyond 90 percent efficiency. The scientists determined orientation angles of the nanofins using equations derived in the study to experimentally demonstrate multichannel polarization multiplexing. Holography is a powerful tool that can reconstruct wavefronts of light and combine the fundamental wave properties of amplitude, phase, polarization, wave vector and frequency. Smart multiplexing techniques (multiple signal integration) together with metasurface designs are currently in high demand to explore the capacity to engineer information storage systems and enhance optical encryption security using such metasurface holograms. The scientists first derived a multiplexing algorithm to support the dynamic vectorial holographic display and encryption process. By using the correct polarization keys, the receiver could obtain the exact information delivered. By increasing the complexity of such images, even higher flexibility was obtained alongside detailed analysis of the reconstructed vectorial image properties. Since the device containing metasurfaces is compact in size, in practice, it can be easily transported with encoded information. , Nature Communications To pattern the design of interest, Zhao et al. engineered several dielectric silicon metasurfaces on top of a glass substrate using plasma etching, followed by electron beam lithography. The metasurfaces were composed of 1000 x 1000 nanofins, i.e. nanostructures with the ability to augment heat transfer via surface area enhancement and liquid-solid-interactions. The researchers studied two schemes of multiple polarization channels; with or without rotation using the birefringent dielectric metasurfaces—to realize the holograms. 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. a) Schematic illustration of an amorphous silicon nanofin positioned on a glass substrate. The metasurface will be composed of a periodic arrangement of such unit-cells. b–e) Simulation results for the amplitude and phase of the transmission coefficients txx and tyy shown for a 2D parameter optimization by using a rigorous coupled wave analysis method. The length and width of the nanofin are both swept in the range of 80–280 nm at an incident wavelength of 800 nm. Credit: Light: Science & Applications, doi: 10.1038/s41377-018-0091-0. Experimental setup and scanning electron microscopy images of the fabricated metasurface samples. a) The experimental setup for the observation of the holographic images. The two linear polarizers (LP1, LP2) and two quarter-wave plates (QWP1, QWP2) are used to set the precise polarization combination for the incident/transmitted light. The lens images the back focal plane of the microscope objective lens (×40/0.6) to a CCD camera. b–e) Scanning electron microscopy images of two typical fabricated silicon metasurface samples shown with a top and side view. The metasurface holograms are composed of 1000 × 1000 nanofins with different cross-sections and orientation angles. Credit: Light: Science & Applications, doi: 10.1038/s41377-018-0091-0. The two-channel polarization and angle-multiplexed hologram represents a cartoon tiger, cartoon snowman, teapot and teacup. Credit: Light: Science & Applications, doi: 10.1038/s41377-018-0091-0. , Nature Nanotechnology Multichannel polarization-multiplexed holograms (“Dice”). Credit: Light: Science & Applications, doi: 10.1038/s41377-018-0091-0. More information: Ruizhe Zhao et al. Multichannel vectorial holographic display and encryption, Light: Science & Applications (2018). DOI: 10.1038/s41377-018-0091-0 Guoxing Zheng et al. Metasurface holograms reaching 80% efficiency, Nature Nanotechnology (2015). DOI: 10.1038/nnano.2015.2 Lingling Huang et al. Three-dimensional optical holography using a plasmonic metasurface, Nature Communications (2013). DOI: 10.1038/ncomms3808 Journal information: Light: Science & Applications Holography based on metasurfaces is a promising candidate for applications in optical displays/storage with enormous information bearing capacity alongside a large field of view compared to traditional methods. To practically realize metasurface holograms, holographic profiles should be encoded on ultrathin nanostructures that possess strong light-matter interactions (plasmonic interactions) in an ultrashort distance. Metasurfaces can control light and acoustic waves in a manner not seen in nature to provide a flexible and compact platform and realize a variety of vectorial holograms, with high dimensional information that surpass the limits of liquid crystals or optical photoresists. Among the existing techniques employed to achieve highly desired optical properties, polarization multiplexing (multiple signal integration) is an attractive method. The strong cross-talk associated with such platforms can, however, be prevented with birefringent metasurfaces (two-dimensional surfaces with two different refractive indices) composed of a single meta-atom per unit-cell for optimized polarization multiplexing.Nevertheless, the full capacity of all polarization channels remains to be explored for improved information storage capacity within metasurface holograms and in holographic optical devices. In a recent study, Ruizhe Zhao and co-workers demonstrated a new method to realize multichannel vectorial holography for dynamic display and high-security applications. In the study, birefringent metasurfaces were explored to control polarization channels and process very different information through rotation. The reconstructed vectorial images could be switched from one form to another with negligible cross-talk by selecting a combination of input/output polarization states. The results are now published in Light: Science & Applications. The scientists were able to design and construct more complex multiplexing functionalities with 12 channels using the same principles of design thereafter. The vectorial images were viewed as holographic reconstructions with the input/output polarization combinations developed as proposed. The technique could also be used to encrypt different images at the same spatial location. In encryption, such superposition can convey a different meaning on reconstruction. As an example, the scientists chose the image of a die with six representative surfaces, and by using different combinations of input/output polarization states, encoded up to six images for viewing.The multiplexing algorithm derived in the study aided the dynamic vectorial holographic display and the encryption of images encoded on birefringent dielectric metasurfaces. By using the correct polarization keys, a receiver could obtain the exact information delivered. Higher flexibility could be obtained by increasing the complexity of the image and changing the medium of encryption to titanium dioxide (TiO2) or silicon nitride (SiN). The correct polarization combination secured the information for enhanced complexity during decryption.The multichannel hologram maintained a relatively large working bandwidth since the reconstructed images could be observed away from the designed wavelength of 800 nm. The study established a design and engineering technique that combined birefringent properties of simple nanofins used as the building blocks, with extra-design freedom of rotation matrix and smart multiplexing algorithms. The results enabled high-dimensional multichannel polarization multiplexed holograms, with up to 12 polarization channels. In this way, efficient light-based encryption and integrated multichannel holographic display techniques can pave the way for advanced communication in high security applications. Principle of the metasurface holography design and statistical results of the number of each nanofin (different cross-sections and orientation angles) contained in the designed metasurface holograms. Schematic illustrations of polarization multiplexed holograms based on dielectric metasurfaces. The red and blue arrows indicate the polarization of the incident light and the transmission axis of the polarizer placed behind the metasurface sample. The red, blue, and green color of the reconstructed images (the words “holography”, “meta”, and “surface”) represent components of the output light, respectively. a) Two channel polarization and an angle multiplexed hologram based on metasurfaces composed of nanofins with different cross-sections but fixed orientation angles, which can be used to reconstruct two sets of off-axis images. b) Multichannel polarization multiplexed hologram based on metasurfaces composed of nanofins with different cross-sections and orientation angles, which can be used to reconstruct three independent images and all combinations of these images (12 channels in total). c) Two-channel polarization- and angle-multiplexed hologram (enables appearance of “cartoon tiger”, “cartoon snowman”, “teapot”, “cup”), b) Multichannel polarization-multiplexed hologram (appearance of the word “holography”, “meta”, “surface”) c) Multichannel polarization-multiplexed hologram (appearance of “dice”) d Multichannel polarization-multiplexed hologram (appearance of a “cartoon person”). Credit: Light: Science & Applications, doi: 10.1038/s41377-018-0091-0. © 2018 Science X Network For optical characterization of the metasurface holograms, Zhao et al. used an experimental setup. The magnifying ratio and numerical aperture of the objective lens were carefully chosen to collect all the diffraction light from the sample and reconstruct holographic images in the Fourier plane. The scientists used a second objective/lens to capture the Fourier plane on a CCD camera. They also separately observed two scanning electron microscopy images of the samples with or without rotation to characterize the engineered surface.As a proof-of-principle, using the metasurfaces, Zhao et al. constructed holographic images of a cartoon tiger and a snowman that appeared with high fidelity and high resolution when illuminated by x-polarized light. When the incident light was switched to y-polarization, the reconstructed images changed to a teapot and a teacup. In this experiment, only two polarization channels were available in the setup, with both pairs of the holographic images reconstructed and made to disappear simultaneously by rotating the polarizer behind the sample. The experimental results were in agreement with the simulation to confirm the study’s fundamental design principle. The net diffraction efficiency of the hologram was defined as the ratio of intensity of the single reconstructed image to the power of incident light. Explore further Citation: Multichannel vectorial holographic display and encryption (2018, December 7) retrieved 18 August 2019 from https://phys.org/news/2018-12-multichannel-vectorial-holographic-encryption.html Technique makes more efficient, independent hologramslast_img read more

first_img 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. More information: J. Menezes, B. Moura, and T.A. Pereira. “Uneven rock-paper-scissors models: Patterns and coexistence.” EPL. DOI: 10.1209/0295-5075/126/18003 Traditionally, the rock-paper-scissors model assumes that all three species have equal strength. But what if one of the species is weaker than the other two? Such a scenario may occur in nature, for example, due to seasonal variations that reduce the ability of a certain species to compete with other species. In a new paper, associate professor Josinaldo Menezes, graduate student Tibério Pereira, and undergraduate student Bia Moura at the Federal University of the Rio Grande do Norte in Brazil have addressed this question by performing more than a million simulations of a rock-paper-scissors model in which one species attacks less than it is attacked. The model helps to explain how coexistence among different species is maintained in spite of the species’ different strengths.”The results tell us that the reason why species may coexist, even if one of them is weaker, is the special selection configuration of the rock-paper-scissors model,” Pereira told Phys.org.The model works somewhat differently than the original rock-paper-scissors model when implemented as a special case of the May-Leonard model. Individuals, which are placed on a grid, can carry out three possible interactions, no matter which of the three species they belong to. The three interactions are selection, mobility, and reproduction. Selection is like killing, in which an individual of one species can wipe out a neighboring individual of the species that it dominates. For mobility, an individual of one species can switch places with a neighboring individual of the species that it dominates, or move to a neighboring empty space. For reproduction, an individual of one species can populate an empty neighboring space with another individual of its species.In the simulation, individuals of each species are randomly distributed on a grid. An individual is randomly selected, and then one of its eight neighboring sites (occupied or empty) is randomly selected. Next one of the three interactions (selection, mobility, or reproduction) is randomly chosen. The chosen individual carries out the interaction, if possible. In some cases, the interaction is not possible: for example, the neighboring site must be occupied by an individual of the correct species (the one being dominated) in order for selection to take place, and the neighboring site must be empty in order for reproduction to take place. In 1975, R.M. May and W.J. Leonard first used the rock-paper-scissors game to model ecological scenarios in which three species cyclically dominate each other: one species dominates a second species, the second species dominates a third species, and the third species dominates the first species. The game works well, for example, for modeling different strains of cyclically dominant E. coli bacteria. To make one species weaker than the other two, the researchers gave one species a lower probability of getting the selection interaction. The results of the simulations showed that, contrary to what might be expected, the weaker species does not necessarily die out. Instead, for some weakness levels, the weaker species initially dominates almost all of the territory. This happens because, since the weaker species selects (i.e., kills) fewer individuals of the species that it dominates, this species grows and, in turn, limits the growth of the third species. As this third species dominates the weaker species, its limited growth allows the weaker species to grow.For these reasons, previous research has shown that the weaker species may always dominate, even in the long run. However, here the researchers found something different.”We were surprised because the weaker species does not necessarily win the uneven rock-paper-scissors game, as it was known in the literature,” Menezes said. “We found out that, in May-Leonard-type simulations, the winner species depends on the mobility and the strength of the weaker species.”Over time, new patterns appear showing exactly how the different species spatially coexist. In particular, spiral patterns emerge and travel like waves until they meet each other, at which point they result in all three species coexisting in small colonies. The spiral patterns—and resulting coexistence—are more likely to occur on larger grids, since this increases the mobility of all species and allows for the species to come in contact with each other. “Beautiful spiral waves emerge when the lattice is almost dominated by one single species,” said Moura. “The formation of spiral spatial patterns is entirely different from the standard rock-paper-scissors model. We expect that our results can be helpful to ecologists because they describe and quantify patterns which are crucial to understanding how such species coexist.”The results also revealed that coexistence has its limits: When the strength of the weaker species is less than approximately one-third of the strength of the other two species, the probability of coexistence greatly diminishes. In the future, the researchers plan to investigate more complex scenarios, such as adaptive biological systems, where a species can change the interaction probabilities to guarantee its survival. They also plan to explore how biological interactions can balance the uneven relationships among species, as well as the effects of diseases and other predators. “We aim to understand how a disease outbreak or a common predator mediation increases the chances of coexistence in the uneven rock-paper-scissors model,” Menezes said. (Top) The selection interactions among three species. The dashed arrow indicates that species 1 is weaker than species 2 and 3. (Bottom) Some of the spatial patterns that emerge in simulations. Individuals of species 1, 2, and 3 are represented by orange, dark blue, and light blue dots, respectively. Empty spaces are represented by white dots. Credit: Menezes et al. ©2019 EPL Explore further Citation: The rock-paper-scissors game and coexistence (2019, July 4) retrieved 18 August 2019 from https://phys.org/news/2019-07-rock-paper-scissors-game-coexistence.html High diversity on coral reefs—a very big game of rock-paper-scissors Journal information: Europhysics Letters (EPL) © 2019 Science X Networklast_img read more

first_imgOctober 26, 2009 After a week of intensive composing and rehearsals, Difference Skies delivered their final performance on Saturday October 24, 2009. On the night of the performance, the Colly Soleri Music Amphitheater was illuminated under the night sky and the audience huddled together around the amphitheater. The musicians and visual artists together created a stunning tapestry of improvised and composed space music, ambient, experimental, and electronic, mixed with interactive video synthesis, for the audience. [photo: Alfonso Elia & text: Anna Tran] After the formal part of the program and a brief intermission, the artists played numerous spontaneously improvised pieces, stirring the awe and imagination of the audience. [photo: tt & text: Anna Tran] The Different Skies performance was absolutely astounding. Thank you and congratulations to all who helped bring this wonderful performance together. We hope to see you all again next year! [photo: Alfonso Elia & text: Anna Tran]last_img read more