458 research outputs found

    Analysis of Parametric Oscillatory Instability in Power Recycled LIGO Interferometer

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    We present the analysis of a nonlinear effect of parametric oscillatory instability in power recycled LIGO interferometer with the Fabry-Perot (FP) cavities in the arms. The basis for this effect is the excitation of the additional (Stokes) optical mode and the mirror elastic mode, when the optical energy stored in the main FP cavity main mode exceeds the certain threshold and the frequencies are related so that sum of frequencies of Stokes and elastic modes are approximately equal to frequencyof main mode. The presence of anti-Stokes modes (with frequency approximately equal to sum of frequencies of main and elastic modes) can depress parametric instability. However, it is very likely that the anti-Stokes modes will not compensate the parametric instability completely.Comment: 9 pages, 2 figures. submitted to Physics Letters

    Genetic diversity among Colletotrichum sublineolum pathotypes isolated from sorghum (Sorghum bicolor).

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    Sorghum anthracnose, caused by Colletotrichum sublineolum is a serious disease in Brazil. The fungus is highly variable pathogenically with many physiological races. The present study was made to evaluate the usefulness of molecular methods (SDS-PAGE, RAPD, ARDRA and rDNA sequencing) for identifying C. sublineolum pathotypes isolated from sorghum. Although protein profile (SDS-PAGE) showed a relative low level of polymorphism, differences could be observed due to presence/absence of some polypeptides as well as to intensity of some bands among pathotypes. DNA profile of arbitrarily amplified sequences (RAPD) using sixteen random primers revealed a high degree of polymorphism while amplified rDNA (ITS region and 18S gene) digested with six different restriction enzymes (ARDRA) showed similar patterns. Nucleotide sequencing analysis of the complete ITS region and partial sequencing of 18S rRNA gene were useful for revealing genetic differences among the five pathotypes. In the present study, RAPD and rDNA sequencing were the most profitable methods for identifying C. sublineolum pathotypes. A antracnose do sorgo, causada por Colletotrichum sublineolum, é séria doença, no Brasil. O fungo é altamente variável do ponto de vista patogênico e várias raças têm sido noticiadas. Este estudo foi realizado com o objetivo de avaliar a utilidade de métodos moleculares (SDS-PAGE, RAPD, ARDRA e seqüenciamento de rDNA) para identificar patótipos de C. sublineolum isolados do sorgo. Embora o perfil protéico (SDS-PAGE) tenha mostrado baixo grau de polimorfismo, foi possível observar diferenças devido à presença/ausência de alguns polipeptídios, bem como diferenças quanto à intensidade de algumas bandas. O perfil de DNA amplificado arbitrariamente (RAPD), usando dezeseis primers aleatórios, revelou elevado grau de polimorfismo entre os patótipos, enquanto que o produto da amplificação de rDNA (região ITS e gene 18S), digerido com seis enzimas de restrição diferentes (ARDRA), apresentou padrão similar. Análise de nucleotídeos da seqüência completa da região ITS e do seqüenciamento parcial do gene 18S rRNA revelaram diferenças genéticas entre os cinco patótipos. Entre os métodos testados no presente estudo, RAPD e seqüenciamento de rDNA foram mais efetivos para identificar patótipos de C. sublineolum

    Assessment of electrophoresis and electroosmosis in construction materials: effect of enhancing electrolytes and heavy metals contamination

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    Electrokinetic effects are those that take place by application of an electric field to porous materials, with the zeta potential as the key parameter. Specifically, in the case of contaminated construction materials, the generation of an electroosmotic flux, with the corresponding dragging due to water transport, is a crucial mechanism to succeed in the treatment of decontamination. Therefore, it is of great interest trying to optimize the treatment by the addition of specific electrolytes enhancing the electrokinetic phenomena. Most of the data of zeta potential found in literature for construction materials are based in micro-electrophoresis measurements, which are quite far of the real conditions of application of the remediation treatments. In this paper, electrophoretic and electroosmotic experiments, with monolithic and powdered material respectively, have been carried out for mortar, brick and granite clean and contaminated with Cs, Sr, Co, Cd, Cu and Pb. The electrolytes tested have been distilled water (DW), Na2–EDTA, oxalic acid, acetic acid and citric acid. The zeta potential values have been determined through the two different techniques and the results compared and critically analysed

    Probiotics, prematurity and neurodevelopment: Follow-up of a randomised trial

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    Objective: To determine the impact of one probiotics combination on the neurodevelopment of very preterm children at 2–5 years corrected gestational age (CA). Design: Follow-up study of survivors of a double-blinded, placebo-controlled, randomised trial of probiotic effects on late-onset sepsis in very preterm infants that found reduced necrotising enterocolitis. Setting: 10 tertiary perinatal centres in Australia and New Zealand. Patients: 1099 very preterm infants born <32 weeks’ gestation and weighing <1500 g. Intervention: Probiotics (Bifidobacterium infantis, Streptococcus thermophilus and Bifidobacterium lactis) or placebo administered from birth until discharge home or term CA, whichever came sooner. Main outcome measures: Major neurodevelopmental impairment comprised any of moderate/severe cerebral palsy (Gross Motor Function Classification System score 2–5), motor impairment (Bayley-III Motor Composite Scale <–2SD or Movement Assessment Battery for Children <15th centile if ≫42 months’ CA), cognitive impairment (Bayley-III Composite Cognitive or Language Scales <–2SD or Wechsler Preschool and Primary Scale of Intelligence Full Scale Intelligence Quotient <–2SD if ≫42 months’ CA), blindness or deafness. Results: Outcome data were available for 735 (67%) participants, with 71 deaths and 664/1028 survivors assessed at a mean age of 30 months. Survival free of major neurodevelopmental impairment was comparable between groups (probiotics 281 (75.3%) vs placebo 271 (74.9%); relative risk 1.01 (95% CI 0.93 to 1.09)). Rates of deafness were lower in probiotic-treated children (0.6% vs 3.4%). Conclusion: Administration of the probiotics combination Bifidobacterium infantis, Streptococcus thermophilus and Bifidobacterium lactis to very preterm babies from soon after birth until discharge home or term CA did not adversely affect neurodevelopment or behaviour in early childhood

    HAWC Study of Very-High-Energy γ\gamma-ray Spectrum of HAWC J1844-034

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    Recently, the region surrounding eHWC J1842-035 has been studied extensively by gamma-ray observatories due to its extended emission reaching up to a few hundred TeV and potential as a hadronic accelerator. In this work, we use 1,910 days of cumulative data from the High Altitude Water Cherenkov (HAWC) observatory to carry out a dedicated systematic source search of the eHWC J1842-035 region. During the search we have found three sources in the region, namely, HAWC J1844-034, HAWC J1843-032, and HAWC J1846-025. We have identified HAWC J1844-034 as the extended source that emits photons with energies up to 175 TeV. We compute the spectrum for HAWC J1844-034 and by comparing with the observational results from other experiments, we have identified HESS J1843-033, LHAASO J1843-0338, and TASG J1844-038 as very-high-energy gamma-ray sources with a matching origin. Also, we present and use the multi-wavelength data to fit the hadronic and leptonic particle spectra. We have identified four pulsar candidates in the nearby region from which PSR J1844-0346 is found to be the most likely candidate due to its proximity to HAWC J1844-034 and the computed energy budget. We have also found SNR G28.6-0.1 as a potential counterpart source of HAWC J1844-034 for which both leptonic and hadronic scenarios are feasible.Comment: 13 pages, 9 figures, published in Ap
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