415 research outputs found

    Hybrid confinement of optical and mechanical modes in a bullseye optomechanical resonator

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    Optomechanical cavities have proven to be an exceptional tool to explore fundamental and technological aspects of the interaction between mechanical and optical waves. Such interactions strongly benefit from cavities with large optomechanical coupling, high mechanical and optical quality factors, and mechanical frequencies larger than the optical mode linewidth, the so called resolved sideband limit. Here we demonstrate a novel optomechanical cavity based on a disk with a radial mechanical bandgap. This design confines light and mechanical waves through distinct physical mechanisms which allows for independent control of the mechanical and optical properties. Our device design is not limited by unique material properties and could be easily adapted to allow large optomechanical coupling and high mechanical quality factors with other promising materials. Finally, our demonstration is based on devices fabricated on a commercial silicon photonics facility, demonstrating that our approach can be easily scalable.Comment: 16 pages, 11 figure

    Comunicación gubernamental pre-covid de los presidentes hispanohablantes en Twitter

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    On March 11, 2020, the World Health Organization (WHO) officially declared the state of a coronavirus pandemic (SARS-CoV-2) in the world. A statement unprecedented in history, but that the media had been reporting since the previous weeks. With the general objective of analyzing the political communication and media competence that the presidents of the Spanish-speaking countries had the week before the declaration of a pandemic by COVID19, we chose a quantitative investigation due to its importance in data analysis with a flexible method. Through mining with advanced data search algorithms on Twitter, we analyzed 7.650 tweets from the accounts of the 22 presidents and 21 media outlets. Despite the indicators of the WHO and the media, many of the presidents did not have an acceptable political communication and media competence according to the problem addressed.El 11 de marzo de 2020 la Organización Mundial de la Salud (OMS) declaró oficialmente el estado de pandemia por coronavirus (SARS-CoV-2) en el mundo. Una declaración sin precedentes en la historia, pero que desde las semanas previas los medios de comunicación ya estaban informando. Con el objetivo general de analizar la comunicación política y competencia mediática que tuvieron los presidentes de los países hispanohablantes la semana previa a la declaración de pandemia por COVID19, escogimos una investigación cuantitativa por su importancia en el análisis de datos con un método flexible. Mediante la minería con algoritmos de búsqueda avanzada de datos en Twitter analizamos 7.650 tuits de las cuentas de los 22 presidentes y 21 medios de comunicación. A pesar de los indicadores de la OMS y los medios de comunicación, muchos de los presidentes no tuvieron una comunicación política y competencia mediática aceptable acorde con el problema abordado

    Brillouin Optomechanics In Coupled Silicon Microcavities

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The simultaneous control of optical and mechanical waves has enabled a range of fundamental and technological breakthroughs, from the demonstration of ultra-stable frequency reference devices, to the exploration of the quantum-classical boundaries in optomechanical laser-cooling experiments. More recently, such an optomechanical interaction has been observed in integrated nano-waveguides and microcavities in the Brillouin regime, where short-wavelength mechanical modes scatter light at several GHz. Here we engineer coupled optical microcavities to enable a low threshold excitation of mechanical travelling-wave modes through backward stimulated Brillouin scattering. Exploring the backward scattering we propose silicon microcavity designs based on laterally coupled single and double-layer cavities, the proposed structures enable optomechanical coupling with very high frequency modes (11 to 25 GHz) and large optomechanical coupling rates (g(0)/2 pi) from 50 kHz to 90 kHz.7Sao Paulo State Research Foundation (FAPESP) [2012/17765-7, 2012/17610-3]National Counsel of Technological and Scientific Development (CNPQ)Coordination for the Improvement of Higher Education Personnel (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    Quality improvement activities associated with organisational capacity in general practice

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    Copyright © 2007 Australian College of General Practitioners Copyright to Australian Family Physician. Reproduced with permission. Permission to reproduce must be sought from the publisher, The Royal Australian College of General Practitioners.BACKGROUND Clinical audit is recognised worldwide as a useful tool for quality improvement. METHODS A feedback report profiling capacity for chronic disease care was sent to 97 general practices. These practices were invited to complete a clinical audit activity based on that feedback. Data were analysed quantitatively and case studies were developed based on the free text responses. RESULTS Eighty-two (33%) of 247 general practitioners participated in the clinical audit process, representing 57 (59%) of 97 general practices. From the data in their feedback report, 37 (65%) of the 57 practices recognised the area most in need of improvement. This was most likely where the need related to clinical practice or teamwork, and least likely where the need related to linkages with other services, and business and finance. Only 25 practices (46%) developed an action plan related to their recognised area for improvement, and 22 (39%) practices implemented their chosen activity. Participating GPs judged that change activity focused on teamwork was most successful. DISCUSSION The clinical audit process offered participating GPs and practices an opportunity to reflect on their performance across a number of key areas and to implement change to enhance the practice’s capacity for quality chronic disease care. The relationship between need and action was weak, suggesting a need for greater support to overcome barriers.Cheryl Amoroso, Judy Proudfoot, Tanya Bubner, Edward Swan, Paola Espinel, Christopher Barton, Justin Beilby and Mark Harri

    Utilización del polimorfismo del ADN de cloroplastos para definir regiones de procedencia materna en los robles blancos de la Península Ibérica

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    We present here the results obtained after the study of 156 oak populations collected along the Iberian Peninsula. Six oak species were present in the sample: Quercus canariensis, Q. faginea, Q. humilis, Q. pyrenaica, Q. robur and Q. petraea. Five trees from each population were analyzed with four cpDNA specific pairs of primers that allowed the distinction of 13 haplotypes. In populations with several species, all of them shared the same haplotype, and none of the common haplotypes was restricted to a single species. Analysis of molecular variance in the data revealed a strong genetic structure. Maternal provenance regions were defined that maximize the among groups variance and minimize the among populations/within groups variance. The distribution of the haplotypes suggests the existence of several distinct refugia, not restricted to the South of the Peninsula.En este trabajo se presentan los resultados obtenidos tras el estudio de 156 poblaciones de robles a lo largo de la Península Ibérica. Los robles estudiados pertenecen a seis especies: Quercus canariensis, Q. faginea, Q. humilis, Q. pyrenaica, Q. robur y Q. petraea. Se analizaron cinco árboles de cada población con cuatro pares de cebadores específicos de cpADN, lo que permitió distinguir un total de 13 haplotipos. En las poblaciones en las que había varias especies, generalmente todas mostraron el mismo haplotipo; y ninguno de los haplotipos comunes representa a una sola especie. El análisis de la varianza molecular (AMOVA) ha revelado una fuerte estructura genética. Las regiones de procedencia materna se definieron de tal manera que se maximizara la varianza entre grupos y minimizara la varianza entre poblaciones dentro de grupos. Por último, la distribución de haplotipos sugiere la existencia de diversos refugios glaciares no restringidos únicamente al sur de la Península

    Brillouin scattering self-cancellation

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORThe interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin scattering in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain-induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result, proper material and structure engineering allows one to control each contribution individually. Here, we experimentally demonstrate the perfect cancellation of Brillouin scattering arising from Rayleigh acoustic waves by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon-phonon interaction, enhancing or suppressing it.The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin scattering in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain-induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result, proper material and structure engineering allows one to control each contribution individually. Here, we experimentally demonstrate the perfect cancellation of Brillouin scattering arising from Rayleigh acoustic waves by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon-phonon interaction, enhancing or suppressing it.718FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR08/57857-2, 2012/17610-3, 2012/17765-7, 2013/20180-3574017/2008-9Sem informaçã

    Design and Construction Methods of Caisson-Type Maritime Infrastructures Using GFRP

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    Glass-fiber-reinforced polymers (GFRPs) are commonly used in various applications in civil-engineering projects. However, they are not common in the construction of civil-marine structures. The GFRP caisson technology was developed for the construction of two mooring dolphins in Puerto el Rosario (Fuerteventura, Spain). Ultraviolet-protected glass-fiber and epoxy resin coats were used to build a 12-m diameter, 13.3-m high cylindrical structure. A finite-element model was used to verify the sandwich composite configuration using the Tsai?Hill criteria?the shear strength of the skins and honeycomb core and the buckling and local failure modes with respect to the composite configuration. This is the first time that the two caissons were designed and built of polymeric materials and installed in a seaport. Accordingly, the construction technique marks a milestone in civil engineering because of its highly innovative nature in addition to significantly reducing the time associated with and the complexity of construction operations

    Statistical analyses of correlation between fluconazole MICs for Candida spp. assessed by standard methods set forth by the European Committee on Antimicrobial Susceptibility Testing (E.Dis. 7.1) and CLSI (M27-A2).

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    The European Committee on Antimicrobial Susceptibility Testing (EUCAST) Subcommittee on Antifungal Susceptibility Testing recently published a standard for determining the susceptibility of fermentative yeasts to antifungals. From the beginning, the EUCAST and its North American counterpart, the CLSI, decided to work together in order to establish common standards. As part of this exercise, the susceptibility of a set of 475 yeast isolates was tested by both standards. The intraclass correlation coefficient and the equations defining the linear regression between both methods were estimated. Both methods produced very similar results, with an intraclass correlation coefficient of 0.954 (0.945 to 0.962), although linear regression analysis shows that the EUCAST standard resulted in slightly lower MICs. There were only eight isolates showing at least four twofold dilution MIC differences between both standards. After 24 h of incubation, the MICs obtained by the CLSI method were equivalent to those obtained by the EUCAST standard. In summary, both methods produce very similar MICs, indicating that methodology does not pose any obstacle to obtaining uniform standards for antifungal susceptibility testing of yeast

    Comparación de la eficacia y la productividad de tres granulovirus nativos sobre larvas de Tecia solanivora (Povolny) (Lepidoptera: Gelechiidae)

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    Tecia solanivora is one of the most limiting potato pests and the use of granulovirus constitutes a promissory alternative for its control. A biopesticide based on a granulovirus isolate from Peru is manufactured in Colombia, for controlling the pest under storage conditions. In a previous work, three native granulovirus from T. solanivora larvae from the localities of Chocontá, Mosquera and Carmen de Carupa of the Cundinamarca department were isolated. These native strains could be better adapted to both the host and the environmental conditions of the country. In the present work the three native isolates of granulovirus were evaluated formulated and unformulated under laboratory conditions by using a bioassay and were compared with the Peruvian strain. The formulated native viruses presented the highest efficacy with results between 88% and 100%, while the Peruvian isolate obtained 88%. These results were significantly different from the obtained with the unformulated virus isolates, for which the efficacy ranged between 36% and 86% for native isolates and was 59% for the Peruvian strain. The concentration of occlusion bodies (OB) produced per milligram of larva tissue was measured and no significant differences between the isolates were observed. The average yield was 4.4 x 107 OB/mg larvae. Results allowed to select the native isolate from Mosquera (Cundinamarca) for a future biopesticide development for presenting the highest virulence levels.  Tecia solanivora es una de las plagas más limitantes del cultivo de la papa, para cuyo control el uso de granulovirus constituye una alternativa promisoria. Para el control de la plaga en condiciones de almacenamiento, en Colombia se produce un bioplaguicida en polvo a base de un granulovirus aislado en Perú a partir de larvas de Phthorimaea operculella. En un trabajo previo se aislaron tres granulovirus nativos provenientes de larvas de T. solanivora de los municipios de Chocontá, Mosquera y Carmen de Carupa en el departamento de Cundinamarca, los cuales podrían estar mejor adaptados al insecto y a las condiciones ambientales del país. En el presente trabajo, los tres aislamientos de granulovirus se evaluaron mediante un bioensayo en laboratorio utilizándolos formulados y sin formular y teniendo como patrón de comparación la cepa peruana. Los virus nativos formulados presentaron eficacias entre 88% y 100%, mientras que para el aislamiento peruano se obtuvo 88%. Estos resultados fueron significativamente diferentes de los obtenidos con los aislamientos sin formular, para los cuales la eficacia estuvo entre 36% y 86% para los aislamientos nativos y, 59% para el aislamiento peruano. También se comparó la cantidad de cuerpos de inclusión (CI) producidos por miligramo de larva con cada uno de los aislamientos, entre los que no se encontraron diferencias significativas. El rendimiento promedio fue de 4,4 x 107 CI/mg de larva. Los resultados permitieron seleccionar el aislamiento nativo proveniente de Mosquera (Cundinamarca) para el futuro desarrollo de un bioplaguicida por presentar los mayores niveles de virulencia.   
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