Celtic Football Club manager Brendan Rodgers has revealed his delight with the competition for places in the club’s midfield position.The Scottish Premiership champions who’ve lost a captain and central midfielder, Scott Brown to injury have been impressive over the last few games.Callum McGregor’s success in the deep-lying playmaker role, coupled with the emergence of Ryan Christie and re-emergence of Scott Sinclair, has provided the Celtic with a balance and propulsion that is allowing them to produce their invincible treble season of two campaigns ago.Speaking about Scott Brown’s potential return to the starting lineup once he returns from injury and the competition the former Scotland international might face, Rodgers said, according to Scotsman:“We want all the boys back,” said the Irishman.”Match Preview: Manchester United vs Leicester City Boro Tanchev – September 13, 2019 Old Trafford is the venue for the Premier League encounter between Manchester United and Leicester City, which kicks off at 16:00 (CET) on Saturday.“But it’s what you want as a coach from the guys who have come into the team. Scott Sinclair looks back to his level, and Ryan [Christie] coming in has been like signing a new player, so it’s brilliant.”Talking about keeping his player’s motivated, the former Liverpool boss said:“That’s your job as manager and coach, to provide a stimulus for players to keep having the hunger.”“Part of that was to bring players in, we wanted to do that but it didn’t happen. Because you can be as good a coach as you want, but sometimes the best stimulus for players is competition. However that’s OK – let’s keep working to how we want to play, and as you saw against Leipzig, they’ve been fantastic.”
Updated: 7:26 PM Posted: April 1, 2019 Categories: Local San Diego News, Politics FacebookTwitter April 1, 2019 Steve Bosh Steve Bosh, SAN DIEGO (KUSI) – San Diego’s years-long-effort to expand the Convention Center has suddenly gotten a lot more difficult.The city decided not to make a 9.4 million dollar payment to gain control of the land needed for expansion.The leaseholder on the five acres of land the city needs for expansion, is held by Fifth Avenue Landing Company, which is committed to building two hotels on the site. Last year the city agreed to pay Fifth Avenue 33 million dollars for the lease, if the voters approved a hotel tax increase that was to happen in 2018.The city was to make three payments this year, the first being 9.4 million, but the vote was delayed until 2020.The land is owned by the port and was leased to 5th avenue in 2010. Five years later, the city wanted to buy the lease from 5th Avenue for 14 million dollars, but defaulted on the payment and the lease reverted back to 5th avenue.The 14 million dollars it would have cost the taxpayers to get the lease in 2015, is now 33 million in 2019. San Diego Convention Center Update
Journal information: Proceedings of the National Academy of Sciences Citation: Cane toad pioneers speed up invasions (2013, July 30) retrieved 18 August 2019 from https://phys.org/news/2013-07-cane-toad-invasions.html 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. Explore further Associate Professor Rick Shine: “The research has implications for how we assess the impact of invasive species.” © 2013 Phys.org More information: Rapid shifts in dispersal behavior on an expanding range edge, PNAS, Published online before print July 29, 2013, doi: 10.1073/pnas.1303157110AbstractDispersal biology at an invasion front differs from that of populations within the range core, because novel evolutionary and ecological processes come into play in the nonequilibrium conditions at expanding range edges. In a world where species’ range limits are changing rapidly, we need to understand how individuals disperse at an invasion front. We analyzed an extensive dataset from radio-tracking invasive cane toads (Rhinella marina) over the first 8 y since they arrived at a site in tropical Australia. Movement patterns of toads in the invasion vanguard differed from those of individuals in the same area postcolonization. Our model discriminated encamped versus dispersive phases within each toad’s movements and demonstrated that pioneer toads spent longer periods in dispersive mode and displayed longer, more directed movements while they were in dispersive mode. These analyses predict that overall displacement per year is more than twice as far for toads at the invasion front compared with those tracked a few years later at the same site. Studies on established populations (or even those a few years postestablishment) thus may massively underestimate dispersal rates at the leading edge of an expanding population. This, in turn, will cause us to underpredict the rates at which invasive organisms move into new territory and at which native taxa can expand into newly available habitat under climate change. Cane toads ‘wiping out’ mini crocodiles Down Under (Phys.org) —Climate change is one of a number of stressors that cause species to disperse to new locations. Scientists must be able to predict dispersal rates accurately, as the movement of a new species into an area can have a significant, and sometimes detrimental, effect on that area’s ecology. When studying dispersal rates of cane toads in Australia, Tom Lindstrom of the University of Sydney and his colleagues found that toads that are first to move into a new area travel at faster rates than toads that arrive later. Their research, published in the Proceedings of the National Academy of Sciences, shows that failure to account for this has caused scientists to severely underestimate dispersal rates. Australia’s Bureau of Sugar Experiment Stations brought cane toads from America to Australia in 1935, in order to control beetles that were infesting sugar cane. Since then, cane toad populations have spread widely, and the toads, which secrete a toxin, disrupt the native ecology. In order to predict how cane toad populations will shift in response to environmental stressors, scientists have been studying movement patterns of established toad populations. Lindstrom and his team contend that by ignoring the differences between “pioneer” toads, who are the first to enter a site, and toads that have been at a site for a few years, previous predictions of dispersal rates have been inaccurate.The team studied eight years worth of data from radio-tracked toads that had colonized a site in tropical Australia. Using a Bayesian model, the researchers analyzed the data and determined that pioneer toads were more likely move in constant directions and take long steps than toads that arrived a few years later. These toads tended to take short steps and frequently make sharp-angled turns. Because of these behavioral differences, toads at the forefront of an invasion covered almost twice as much ground as later-arriving toads.The team found physical differences between the pioneer toads and the other toads that could account for the pioneers’ faster movements. For example, pioneer toads had longer legs. The researchers speculate that because pioneers can only mate with each other, inherited physical differences between pioneers and other toads increase over time. This causes pioneers to continually become more “athletic” in comparison to the other toads. In fact, many of the cane toad pioneers had spinal arthritis, indicating that they had reached physiological or biomechanical tolerance limits. Lindstrom and his team suggest that environmental conditions may enhance the effects of physical “improvements” in pioneer populations; for example, pioneers may find travel during wet seasons easier than their slower conspecifics.The researchers claim that many other species have exhibited rapid dispersal rates during the earliest phases of invasions. By restricting data to that obtained from organisms long-established in an area and ignoring variations in environmental conditions, scientists may routinely be underestimating the speeds at which species can invade new territories.
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. Three teams find a way to measure frequencies with far better precision than previous techniques As Rechtsman notes, optical sensors are used in a variety of applications that involve very slight mechanical vibrations or changes in temperature. They are also used when working with nanoparticles or in the analysis of biomolecules. All such sensors have a single problem, however—their performance is limited by the strength of the perturbations under study. In this new effort, both research teams sought to overcome this limitation by coupling modes of light, allowing them to coalesce—this occurs in places called “exceptional points,” and they only arise in what are known as Hermitian systems. In such systems, prior research has shown, photon loss is a main feature, as opposed to conventional systems in which the opposite is true. In either case, the result is increased sensitivity, which, of course, translates to more precision.In the first effort, the researchers connected three ring-shaped sensors together and then added gold heating elements beneath them to fine tune the sensors and to emulate perturbations. In the second effort, the researchers used just one ring-shaped sensor but sent light around it in both directions (both clockwise and counterclockwise) at the same time to cause coalescence. Then, they used a fiber tip to fine tune the sensor and a second tip to cause perturbations.Both techniques come with a trade-off, Rechtsman notes, between fine-tuning and sensitivity, and there remains the question of whether either or both can be modified to achieve even higher sensitivities. Citation: Two ways to improve optical sensing using different resonator techniques (2017, August 10) retrieved 18 August 2019 from https://phys.org/news/2017-08-ways-optical-resonator-techniques.html Structures called optical resonators trap light at certain frequencies. When the environment of such a resonator is perturbed, these frequencies shift, which allows optical resonators to be used as sensors. a, Hodaei et al. report a sensor that consists of three ring-shaped resonators that are coupled (red arrows). The authors use gold heating elements both to precisely tune the sensor and to emulate perturbations. b, By contrast, Chen et al. use a single toroidal resonator, and couple light that travels in clockwise (blue arrow) and anticlockwise (yellow arrow) directions. The authors use two fibre tips to tune the sensor and another type of tip to introduce perturbations. c, In conventional sensors, the shift in frequency caused by a perturbation is directly proportional to the strength of the perturbation (grey line). Hodaei et al. and Chen et al. demonstrate that the frequency shift in their sensing devices scales with the cube root (red line) or square root (blue line) of the perturbation strength, respectively. This leads to a dramatic improvement in the scaling of sensitivity of such sensors in comparison to conventional devices. Credit: Mikael C. Rechtsman, Nature 548, 161–162 (10 August 2017) doi:10.1038/548161a (Phys.org)—Two independent teams working on research aimed at improving optical sensing have used techniques that involve coupling two or more modes of light such that their modes and their corresponding frequencies coalesce, resulting in more sensitivity. In the first effort, a team from Washington University in St. Lois and Otto-von-Guericke University Magdeburg, in Germany, connected three traditional sensors for more precise tuning. In the second effort, a team from the University of Central Florida and Michigan Technological University used just one resonator but coupled light traveling in both directions around it. Both teams have published papers describing their efforts and results in the journal Nature. Mikael Rechtsman with the Pennsylvania State University offers a News & Views piece outlining optical sensing techniques and the work done by the two teams in the same journal issue. Journal information: Nature © 2017 Phys.org More information: 1. Weijian Chen et al. Exceptional points enhance sensing in an optical microcavity, Nature (2017). DOI: 10.1038/nature23281AbstractSensors play an important part in many aspects of daily life such as infrared sensors in home security systems, particle sensors for environmental monitoring and motion sensors in mobile phones. High-quality optical microcavities are prime candidates for sensing applications because of their ability to enhance light–matter interactions in a very confined volume. Examples of such devices include mechanical transducers, magnetometers, single-particle absorption spectrometers3, and microcavity sensors for sizing single particles and detecting nanometre-scale objects such as single nanoparticles and atomic ions. Traditionally, a very small perturbation near an optical microcavity introduces either a change in the linewidth or a frequency shift or splitting of a resonance that is proportional to the strength of the perturbation. Here we demonstrate an alternative sensing scheme, by which the sensitivity of microcavities can be enhanced when operated at non-Hermitian spectral degeneracies known as exceptional points. In our experiments, we use two nanoscale scatterers to tune a whispering-gallery-mode micro-toroid cavity, in which light propagates along a concave surface by continuous total internal reflection, in a precise and controlled manner to exceptional points. A target nanoscale object that subsequently enters the evanescent field of the cavity perturbs the system from its exceptional point, leading to frequency splitting. Owing to the complex-square-root topology near an exceptional point, this frequency splitting scales as the square root of the perturbation strength and is therefore larger (for sufficiently small perturbations) than the splitting observed in traditional non-exceptional-point sensing schemes. Our demonstration of exceptional-point-enhanced sensitivity paves the way for sensors with unprecedented sensitivity.2. Hossein Hodaei et al. Enhanced sensitivity at higher-order exceptional points, Nature (2017). DOI: 10.1038/nature23280AbstractNon-Hermitian degeneracies, also known as exceptional points, have recently emerged as a new way to engineer the response of open physical systems, that is, those that interact with the environment. They correspond to points in parameter space at which the eigenvalues of the underlying system and the corresponding eigenvectors simultaneously coalesce1, 2, 3. In optics, the abrupt nature of the phase transitions that are encountered around exceptional points has been shown to lead to many intriguing phenomena, such as loss-induced transparency4, unidirectional invisibility5, 6, band merging7, 8, topological chirality9, 10 and laser mode selectivity11, 12. Recently, it has been shown that the bifurcation properties of second-order non-Hermitian degeneracies can provide a means of enhancing the sensitivity (frequency shifts) of resonant optical structures to external perturbations13. Of particular interest is the use of even higher-order exceptional points (greater than second order), which in principle could further amplify the effect of perturbations, leading to even greater sensitivity. Although a growing number of theoretical studies have been devoted to such higher-order degeneracies14, 15, 16, their experimental demonstration in the optical domain has so far remained elusive. Here we report the observation of higher-order exceptional points in a coupled cavity arrangement—specifically, a ternary, parity–time-symmetric photonic laser molecule—with a carefully tailored gain–loss distribution. We study the system in the spectral domain and find that the frequency response associated with this system follows a cube-root dependence on induced perturbations in the refractive index. Our work paves the way for utilizing non-Hermitian degeneracies in fields including photonics, optomechanics10, microwaves9 and atomic physics17, 18. Explore further