SA university choir best in world

first_imgThe victorious Stellenbosch University Choir distinguished itself again at this year’s World Choir Games. (Image: Interkultur) The choir of Stellenbosch University took part in the World Choir Games in Shaoxing, China, in July, and walked off with a world title in two categories.Thousands of entrants gathered in the town in the eastern coastal province of Zhejiang for the sixth edition of the biennial competition, which ran from 15 to 26 July 2010. The World Choir Games is regarded as the largest event of its kind.Over 6 000 choristers in some 470 teams from 83 countries made the long journey to China, among them three South African choirs – the Kearsney College Choir, the Tygerberg Children’s Choir, and the Stellenbosch University (SU) Choir.The SU Choir took gold in both its categories – Mixed Choirs category as well as Musica Contemporanea (contemporary music). In the former category the vocalists battled it out with 28 other choirs, and their second category saw them triumph over 10 rivals.Choir conductor Andre van der Merwe said afterwards: “The SU Choir received the highest overall mark of 95.8%. I am extremely proud of the discipline, passion and dedication of the 112 choir members!”Van der Merwe added that the choir received good television, radio and print exposure, and were thrilled to be ambassadors for their country. They also took part in the champions’ concert.This is not the first time the SU Choir has walked off with top honours at a World Choir Games event – the ensemble took a gold medal in the Musica Sacra category at the previous competition held in Graz, Austria, in 2008, as well as a silver medal for Gospel and Spiritual.The Games move to Cincinnati, US, in 2012.The Tygerberg Children’s Choir, performing under the baton of Hendrik Loock, also returned triumphant with gold medals in the Folklore and Music of the Religions categories.The SU Choir is one of several ensembles in the university’s Department of Music, along with the SU Symphony Orchestra, the Kemus electronic music ensemble, the Schola Cantorum chamber choir and the Symphonic Winds.The oldest university choir in the country, it was founded in 1936 by William Morris, who was also its first choirmaster. Van der Merwe, who took up his post in 2003, is its seventh choirmaster.Besides its live performances, the award-winning choir has released a number of albums.Global harmony through songThe World Choir Games are open to amateur choirs from any country and continent, irrespective of the genres represented in a choir’s repertoire. But participation is by invitation only.The singing festival is organised by German foundation Interkultur, which exists solely to bring people from all cultures together in music and song.The inaugural competition took place in Austria in 2000.“To experience this festival for choirs from all over the world means to participate, to contribute one’s own performance, to compare to others and to experience the enthusiasm of singing together,” said a statement on the Interkultur website.This year the biggest contingent came from Russia, which entered 31 choirs.last_img read more

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Common sense regulatory reform needed for U.S. agriculture

first_imgShare Facebook Twitter Google + LinkedIn Pinterest In mid-May, a Senate committee advanced its version of the Regulatory Accountability Act, a bill that will benefit U.S. agriculture by making federal agencies more accountable and transparent in rule-making.Under the RAA, federal agencies must provide the public with more information regarding the most costly regulations before initiating rule-making; undertake a cost/benefit analysis; select the most cost-effective approach; consider reasonable alternatives to proposed rules; and use the best scientific, technical and economic information.RAA would prohibit agencies from using social media or engaging in propaganda to lobby the public, as the Environmental Protection Agency did when introducing its Waters of the U.S. rule.If enacted, this bipartisan legislation would be the most significant regulatory reform to the Administrative Procedure Act since it was first passed in 1946. The APA drives federal rule-making but was enacted prior to the creation of federal agencies and laws that have profound effects on agriculture, including the Environmental Protection Agency, Clean Water Act, Clean Air Act, Endangered Species Act, Occupational Health and Safety Act, and the Food Safety Modernization Act.The needs, magnitude and impacts of federal regulations are strong reasons for reform of the APA, as are other social factors, including the roles of activism, court litigation and social media in influencing regulations.Some critics have said that the legislation will be too cumbersome and, ultimately, would prevent agencies from issuing rules. On the contrary, the RAA will apply only to major new rules that have more than a $100 million yearly impact. It also requires hearings on rules with more than a $1 billion annual impact, but limits the scope of hearings to genuinely disputed facts.To look at the RAA in context of past regulations, its standards would have applied to about 2.2% of the more than 47,500 rules put in place since 2001. Another analysis conducted by the U.S. Chamber of Commerce showed that of the 32,882 agency regulations issued between 2008 and 2016, less than one-half of 1% would have been subject to any RAA provisions, and only one-tenth of 1% would automatically be subject to RAA because they would impose more than $1 billion in costs.Ironically, with current political pressure to eliminate or roll-back regulations, RAA doesn’t discriminate or differentiate between regulation and deregulation — it applies to both. It potentially could reduce the likelihood of regulatory swings that could be created by policy preferences of ever-changing political majorities.Even with changing political majorities, the need for transparency, sensibility and consideration of the economic costs have been recognized and reflected in executive orders about regulatory planning, regulation and review issued by Presidents Reagan, both Bushes, Clinton, and Obama. RAA codifies many of the best practices for analysis in rule-making enunciated by presidents from both major parties.Farmers and ranchers believe regulations are needed to protect public health, food safety, worker safety, environmental quality and market fairness. They also believe the regulatory system needs to be fair, transparent and faithful to the will of Congress, cost-effective and respective of freedoms. The voices of those affected by rules should be heard and respected in the rule-making process. Reform is long overdue.last_img read more

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California’s Green Code Approved, but Embraced Tepidly by Some

first_imgWith the California Building Standards Commission’s unanimous approval on Tuesday, the state took the green-code lead in the U.S. by adopting building standards that will require green practices in both commercial and residential construction.The mandatory, statewide standards – collectively known as CalGreen – are scheduled to take effect beginning January 2011. CalGreen features wide-ranging sustainability measures, including requirements for the installation of low-flow indoor plumbing (with the aim of reducing water use by 20%), separate metering for indoor and outdoor water use on commercial projects, recycling of at least 50% of construction waste, and use of low-VOC paints and flooring.As noted in stories posted by the Los Angeles Times and the San Francisco Chronicle, the new code, which is expected to raise construction costs only slightly, was supported by most building industry associations, realty associations, and the California Chamber of Commerce. Meanwhile, some environmental groups, including Global Green, the Sierra Club, and the Natural Resources Defense Council, have argued that the code doesn’t go far enough, while objections from other quarters – including some contractors, architects, engineers, and two nonprofit certification specialists, the U.S. Green Building Council and Berkeley-based Build It Green – focus on a provision in the code that allows municipalities to adopt and enforce a more stringent code.Two tiers too confusing?A principal issue with the latter, Elizabeth Echols, director of USGBC’s Northern California chapter, told the Los Angeles Times, is that the two-tier labeling system accompanying the stricter measures will be open to conflicting interpretations and will be difficult for local building inspectors to enforce.“The tiers cause confusion in the marketplace and the potential for builders to label their buildings green without substantiating their claims,” while leaving inspections up to local officials who may not have the technical expertise to verify builders’ claims, Echols said.One cabinet official with Governor Arnold Schwarzenegger’s office countered that GBC resisted the two-tier provision because the group didn’t want its LEED rating system to face more competition in the certification realm, although Matthew Hargrove, a vice president with the California Business Properties Association, pointed out to the Chronicle that many jurisdictions near the coast, including San Francisco, likely will stay with LEED, while inland municipalities likely will lean more toward certification by local officials.Of course it’ll be a while before the effectiveness of various inspection regimens can be determined with some accuracy. Mary Nichols, chairwoman of the California Air Resources Board, noted in the Chronicle post that the Building Standards Commission had tightened its proposal based on the board’s requests. She also acknowledged that even if local certification is not as rigorous as third-party systems, at the very least the state’s green code “is a heck of a lot better than anything we have now.”The full text of California’s new green building code is posted online here.last_img read more

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VIDEO State Rep Dave Robertson Talks With WCTV About His First 7

first_imgWILMINGTON, MA — State Rep. Dave Robertson (D-Tewksbury) recently stopped by WCTV studios to discuss his first 7 months on the job and his committee assignments, as well as several important issues confronting Wilmington, including Olin, Route 38 and the North Wilmington train station.Watch the 30-minute interview between Robertson and WCTV Executive Director Shaun Neville below:— Video Playerhttps://wilmington.vod.castus.tv/vod/dl.php/0/0/1/6/4/3/00164308-e61b-4bb4-82db-aec83c7fc9ee1564592338.989+69375038.033@castus4-wilmington+15645969221564595197430114.vod.1080p.20190731_Discourse_Ep1_Dave_Robertson.mp4Media error: Format(s) not supported or source(s) not foundmejs.download-file: https://wilmington.vod.castus.tv/vod/dl.php/0/0/1/6/4/3/00164308-e61b-4bb4-82db-aec83c7fc9ee1564592338.989+69375038.033@castus4-wilmington+15645969221564595197430114.vod.1080p.20190731_Discourse_Ep1_Dave_Robertson.mp4?_=100:0000:0000:00Use Up/Down Arrow keys to increase or decrease volume.—Like Wilmington Apple on Facebook. Follow Wilmington Apple on Twitter. Follow Wilmington Apple on Instagram. Subscribe to Wilmington Apple’s daily email newsletter HERE. Got a comment, question, photo, press release, or news tip? Email wilmingtonapple@gmail.com.Share this:TwitterFacebookLike this:Like Loading… RelatedNews & Notes From WCTV: Learn About A Bill At The State House That Will Help WCTV & Other Local Access TV StationsIn “Community”ALL POLITICS ARE LOCAL: Robertson & Gordon Endorse Ed Markey With Possible Kennedy Showdown LoomingIn “Government”State Rep. Dave Robertson Announces June Office HoursIn “Government”last_img read more

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Threedimensional femtosecond laser nanolithography of crystals

first_img Explore further Wet etching nanopore lattices engineered by 3DLW in YAG. a) Nanopore lattice etched for 120 hours with average pore dimensions (257 ± 7 nm and 454 ± 13 nm) along x and y directions and 1 mm length along z. b) Vertically overlapping nanopores after 2 h wet etching (average dimensions of 131 ± 5 nm and 1,300 ± 35 nm along x and y, and 1 mm lengths). c) Top optical microscope view of nanopores along the z direction etched for 1 hour (129 ± 6.8 µm length). Credit: Nature Photonics, doi: https://doi.org/10.1038/s41566-018-0327-9 Etching nanopores in YAG along mm to cm scale lengths. (A) Optical microscope side view of etched pores. (B) Optical microscope top view of etched nanopores. (C) SEM side view of etched nanopores. Credit: Nature Photonics, doi: https://doi.org/10.1038/s41566-018-0327-9. Subwavelength diffraction gratings and MOW (micro optical waveguides) in YAG (yttrium aluminum garnet) crystals. a) Image of a centimeter-long, 700 nm pitch grating under visible light illumination. b) Experimental and calculated absolute diffraction efficiencies of a subwavelength grating (700 nm pitch) with 1,070 nm wavelength. Efficiency is calculated as the diffracted power divided by the power incident to the embedded grating. Error bars correspond to the experimental standard deviation of ~0.07%. Inset: scanning electron microscopy (SEM) close-up image of the fabricated grating. c) Optical waveguide with hexagonal structure, 500 nm horizontal pore-to-pore spacing, mean pore size of 166 × 386 nm^2 and 4 mm length. d) Simulated intensity mode profile at 1,550 nm with full-width at half maximums (FWHMs) of 862 nm (vertical) and 972 nm (horizontal). e) Diffraction- limited near-field image of the waveguide output mode measured at 1,550 nm, with a FWHM of ~1.5 µm. Credit: Nature Photonics, doi: https://doi.org/10.1038/s41566-018-0327-9 Within 170 hours, the scientists achieved nanopores with cross-sections of 368 x 726 nm2 and lengths of 3.1 mm; to show that nanopores with millimeter-scale length could be engineered in a single etching step. Nanophotonic devices typically require such lattice dimensions from the micrometric to the centimeter scale, without brittle fracture of the crystal due to excessive stress. In this way, the scientists implemented a scheme to homogenously etch nanostructures and microstructured optical waveguides (MOWs), on the desired scale across the whole sample.To test if the observed selectivity of nanopore etching with YAG was transferrable to other crystal types, the scientists conducted similar experimental nanostructuring with sapphire. They found a parallel nanopore etch rate of ~1 x 105 in sapphire, similar to YAG and higher than the rate previously observed with microchannels etched in sapphire. Ródenas and co-workers formed millimeter-long nanopores in sapphire with cross-sections as small as ~120 nm and tested the feasibility of the method by engineering nanopore lattices etched for 170 hours without fracturing the crystal. The results showed an etching selectivity at a value larger than 1 x 105 at the molecuar level between the modified and pristine crystalline states, hitherto not observed in a photo-irradiated material. The observed value was approximately two orders of magnitude higher than that of alumina etch masks on silicon. Ródenas et al. determined the etching rate of unmodified YAG at ~1 nm/hour. The proposed method allowed the design and fabrication of nanophotonic elements inside a crystal that could provide the desired optical responses, at the subwavelength structure. The scientists were able to control the features of pore direction, size, shape, filling fraction and length of nanopore lattices in YAG crystals by combining 3DLW and wet etching.The YAG lattice was etched for 120 hours to obtain average pore dimensions in the x and y directions. The pore shape and size were controlled by tailoring the laser power and polarization. The diameter of etched nanopores depended on the laser power and could be studied for both linear and circular laser beam polarizations. As limitations of the technique, they found that 3-D photonic structures were characteristically isolated in space, needed supporting walls, and suffered shrinkage and a low optical damage threshold. Optical properties of materials are based on their chemistry and the inherent subwavelength architecture, although the latter remains to be characterized in depth. Photonic crystals and metamaterials have proven this by providing access through surface alterations to a new level of light manipulation beyond the known natural optical properties of materials. Yet, in the past three decades of research, technical methods have been unable to reliably nanostructure hard optical crystals beyond the material surface for in-depth optical characterization and related applications. The capability to control lattice formation down to the nanometer scale will be useful in practical photonic applications. For instance, photonic bandgap lattices can be designed with stopbands in the visible to mid-infrared range in solid-state laser crystals for photonic information technology. To further expand the potential of the 3-D nanolithography technique, Ródenas et al. engineered MOW (microstructured optical waveguides) with different lattice spacings and cavity sizes. They obtained dimensions in the range of a centimeter in length, with 700 nm pitch grating observed under visible light illumination. Ródenas et al. conducted theoretical and simulation methods of the subwavelength gratings prior to their material fabrication. For the numerical simulations, they used the finite element method (FEM) in COMSOL Multiphysics 4.2 software. The scientists used the same FEM software and method to model YAG MOWs prior to fabrication.This ability to create controlled 3-D nanostructures of crystals opens up new routes to design compact, monolithic solid-state lasers. The resulting crystals can incorporate traditional cavity elements (gratings, fibres, microfluidic cooling channels) or novel microresonators inside the crystal. The prospect of engineering large, nanostructured laser crystals will provide a new basis for precision technology in metrological applications and allow for potentially new applications with ultra-strong deformable laser nanofibers in microelectronics and for drug delivery in medicine. © 2019 Science X Network (1). Evolution of pore size and cross-sectional aspect ratio as a function of laser power for linear and circular polarizations in YAG. (A) Power dependence of pore widths (in red) and heights (in blue) for linear (LP) and circular (CP) polarizations, measured from pores etched for 1h. (B) Dependence of cross-sectional pore aspect ratio (height divided by width) for linear and circular polarizations. (2) Etching crisscrossed nanopores. (A) The large index contrast between etched and un-etched pores is depicted in a raw bright-field transmission image. (B) 3D sketch of 90º crossing pores at different vertical offset positions. (C, D) SEM pictures of crossing pores at 90º and different crossing heights. Ag sputtered nanoparticles are also visible on the main surface. (E) Close-up view of the inner smooth surface of a pore. Credit: Nature Photonics, doi: https://doi.org/10.1038/s41566-018-0327-9 Journal information: Nature Photonics In the experiments, the scientists used a standard 3DLW with an ytterbium mode-locked ultrafast fiber laser (1030 nm wavelength and 350 fs pulse duration). A 1.4 numerical aperture (NA) oil-immersion objective was used to tightly focus the laser pulses inside the crystals. Ródenas et al. used computer-controlled XYZ linear stages for 3-D nanopositioning of the samples. After laser irradiation, they laterally polished the crystals to expose the irradiated structures followed by wet chemical etching. For this, the YAG crystals were etched in hot phosphoric acid in deionized water. A key technical limitation of the etching process was the difficulty in refreshing the exhausted acid inside the nanopores fabricated using the method detailed. , Nature Materials (1) Scheme to achieve infinitely long and homogeneously etched nanopore lattices by means of 3D-connecting etching pores. (A) 3D sketch of the vertical etching channels architecture for etching microstructured optical waveguides (MOWs). (B) SEM of a polished cut through a MOW partially revealing 3D etching pores. (C) Microscope top view of an etched array of MOWs with vertical etching channels every 80 µm. (2) Etching mm long pores in sapphire. a) Dark-field image of three arrays of 1-mm-long pores after 170 h of total etching time. Pores on each array were written at ~10 mW and at depths ranging from 4 to 30 µm. b) Example of pores written at medium power (9.4 mW) and 29 µm depth, after 30 min etching. c) Example of two pores written at 24 µm depth and at the photo-modification power threshold (~4 mW) for which no secondary pores are observed. Credit: Nature Photonics, doi: https://doi.org/10.1038/s41566-018-0327-9. 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. Citation: Three-dimensional femtosecond laser nanolithography of crystals (2019, January 15) retrieved 18 August 2019 from https://phys.org/news/2019-01-three-dimensional-femtosecond-laser-nanolithography-crystals.html More information: Airán Ródenas et al. Three-dimensional femtosecond laser nanolithography of crystals, Nature Photonics (2018). DOI: 10.1038/s41566-018-0327-9Markus Deubel et al. Direct laser writing of three-dimensional photonic-crystal templates for telecommunications, Nature Materials (2004). DOI: 10.1038/nmat1155 Amit Banerjee et al. Ultralarge elastic deformation of nanoscale diamond, Science (2018). DOI: 10.1126/science.aar4165 , Science For example, laser lithography developed by the semiconductor industry is a surface-processing technique used for efficient etching of a range of materials, including silicon, silica glass and polymers. The process can produce high-quality two-dimensional (2-D) nanophotonic devices that can be extended to 3-D, which was demonstrated two decades ago with infrared femtosecond laser direct writing. However, the photopolymerized structures are impractical as they cannot be interfaced with other photonic elements. While 3-D nanostructured optical fibres have delivered functionalities well beyond those possible with ordinary unstructured glass to revolutionize nonlinear optics and optical communications, reliable manufacture of materials in crystalline media has remained elusive.Alternative methods include direct machining 3-D nanostructures with laser-induced dielectric breakdown and micro-explosions triggered inside transparent crystals to form voids and induce sub-micrometer structures within them. But such methods occurred at the risk of extended lattice damage and crack propagation. Therefore, despite efforts, a standard method for large-scale, 3-D volume crystal nanostructuring remains to be reported.In a recent study published in Nature Photonics, Airán Ródenas and co-workers at the Institute of Photonics and Nanotechnology and the Department of Physics departed from existing methods of engineering the crystal nanoarchitecture. Instead, they proposed a method whereby the inner chemical reactivity of a crystal, given by its wet etch rate, could be locally modified at the nanoscale to form dense nanopore lattices using multiphoton 3-D laser writing (3DLW). The interdisciplinary scientists showed that centimeter-long empty pore lattices with arbitrary features at the 100 nm scale could be created inside key crystals such as yttrium aluminum garnet (YAG) and sapphire, typically used for practical applications. Ródenas et al. performed direct laser writing before etching, creating the desired pore architecture inside the solid-state laser crystal for photonic applications. New insight into nanopatterning diamond The scientists engineered the photonic structures using circular polarization to reproducibly create air pores in the nanoscale region below 200 nm. The nanophotonic structures (air pore photonic lattices) created in the crystal maintained spatial resolution equivalent to that obtained with state-of-the-art multiphoton polymerization lithography. For practical applications, nanophotonic devices require robust and efficient optical interconnections to form large, complex circuit designs with other optical elements. To achieve this, Ródenas et al. controlled the differential etch rate to maintain large pore lengths between the photomodified volumes and the surrounding crystal. They used scanning electron microscopy (SEM) to observe and prove the 3-D etching process. last_img read more

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