A simulation of weak-light phase-locking for space laser interferometer

A simulation was investigated to better understand the impacts and effects of the additional technical noises on weak-light phase-locking for space laser interferometer. The result showed that the locking precision was limited by the phase readout noise when the laser frequency noise and clock jitter noise were removed, and this result was then confirmed by a benchtop experimental test. The required space laser interferometer noise floor was recovered from the simulation which proved the validity of the simulation program. © Published under licence by IOP Publishing Ltd.National Natural Science Foundation of China/61575209Chinese Academy of Sciences/XDB2303020

Antifungal Streptomyces spp. associated with the infructescences of Protea spp. in South Africa

Common saprophytic fungi are seldom present in Protea infructescences, which is strange given the abundance of mainly dead plant tissue in this moist protected environment. We hypothesized that the absence of common saprophytic fungi in Protea infructescences could be due to a special symbiosis where the presence of microbes producing antifungal compounds protect the infructescence. Using a culture based survey, employing selective media and in vitro antifungal assays, we isolated antibiotic producing actinomycetes from infructescences of Protea repens and P. neriifolia from two geographically separated areas. Isolates were grouped into three different morphological groups and appeared to be common in the Protea spp. examined in this study. The three groups were supported in 16S rRNA and multi-locus gene trees and were identified as potentially novel Streptomyces spp. All of the groups had antifungal activity in vitro. Streptomyces sp. Group 1 had inhibitory activity against all tested fungi and the active compound produced by this species was identified as fungichromin. Streptomyces spp. Groups 2 and 3 had lower inhibition against all tested fungi, while Group 3 showed limited inhibition against Candida albicans and Sporothrix isolates. The active compound for Group 2 was also identified as fungichromin even though its production level was much lower than Group 1. The antifungal activity of Group 3 was linked to actiphenol. The observed antifungal activity of the isolated actinomycetes could contribute to protection of the plant material against common saprophytic fungi, as fungichromin was also detected in extracts of the infructescence. The results of this study suggest that the antifungal Streptomyces spp. could play an important role in defining the microbial population associated with Protea infructescences.The Department of Science and Technology (DST)-National Research Foundation (NRF) Centre of Excellence in Tree Health Biotechnology (CTHB), the National Research Foundation (NRF), the University of Pretoria, South Africa as well as by a National Research Foundation of Korea Grant funded by the Korean Government (Ministry of ICT and Future Planning; No. 2014R1A2A1A11053477). Remove selectedhttp://www.frontiersin.org/Forestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

Antifungal Streptomyces spp. associated with the infructescences of Protea spp. in South Africa

Common saprophytic fungi are seldom present in Protea infructescences, which is strange given the abundance of mainly dead plant tissue in this moist protected environment. We hypothesized that the absence of common saprophytic fungi in Protea infructescences could be due to a special symbiosis where the presence of microbes producing antifungal compounds protect the infructescence. Using a culture based survey, employing selective media and in vitro antifungal assays, we isolated antibiotic producing actinomycetes from infructescences of Protea repens and P. neriifolia from two geographically separated areas. Isolates were grouped into three different morphological groups and appeared to be common in the Protea spp. examined in this study. The three groups were supported in 16S rRNA and multi-locus gene trees and were identified as potentially novel Streptomyces spp. All of the groups had antifungal activity in vitro. Streptomyces sp. Group 1 had inhibitory activity against all tested fungi and the active compound produced by this species was identified as fungichromin. Streptomyces spp. Groups 2 and 3 had lower inhibition against all tested fungi, while Group 3 showed limited inhibition against Candida albicans and Sporothrix isolates. The active compound for Group 2 was also identified as fungichromin even though its production level was much lower than Group 1. The antifungal activity of Group 3 was linked to actiphenol. The observed antifungal activity of the isolated actinomycetes could contribute to protection of the plant material against common saprophytic fungi, as fungichromin was also detected in extracts of the infructescence. The results of this study suggest that the antifungal Streptomyces spp. could play an important role in defining the microbial population associated with Protea infructescences.The Department of Science and Technology (DST)-National Research Foundation (NRF) Centre of Excellence in Tree Health Biotechnology (CTHB), the National Research Foundation (NRF), the University of Pretoria, South Africa as well as by a National Research Foundation of Korea Grant funded by the Korean Government (Ministry of ICT and Future Planning; No. 2014R1A2A1A11053477). Remove selectedhttp://www.frontiersin.org/Forestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

Protons in near earth orbit

The proton spectrum in the kinetic energy range 0.1 to 200 GeV was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at an altitude of 380 km. Above the geomagnetic cutoff the observed spectrum is parameterized by a power law. Below the geomagnetic cutoff a substantial second spectrum was observed concentrated at equatorial latitudes with a flux ~ 70 m^-2 sec^-1 sr^-1. Most of these second spectrum protons follow a complicated trajectory and originate from a restricted geographic region.Comment: 19 pages, Latex, 7 .eps figure

Search for antihelium in cosmic rays

The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320 and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained.Comment: 18 pages, Latex, 9 .eps figure

A Study of Cosmic Ray Secondaries Induced by the Mir Space Station Using AMS-01

The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics experiment that will study cosmic rays in the $\sim 100 \mathrm{MeV}$ to $1 \mathrm{TeV}$ range and will be installed on the International Space Station (ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the space shuttle \emph{Discovery} from June 2 to June 12, 1998, and collected $10^8$ cosmic ray triggers. Part of the \emph{Mir} space station was within the AMS-01 field of view during the four day \emph{Mir} docking phase of this flight. We have reconstructed an image of this part of the \emph{Mir} space station using secondary $\pi^-$ and $\mu^-$ emissions from primary cosmic rays interacting with \emph{Mir}. This is the first time this reconstruction was performed in AMS-01, and it is important for understanding potential backgrounds during the 3 year AMS-02 mission.Comment: To be submitted to NIM B Added material requested by referee. Minor stylistic and grammer change

Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01

A measurement of the cosmic ray positron fraction e+/(e+ + e-) in the energy range of 1-30 GeV is presented. The measurement is based on data taken by the AMS-01 experiment during its 10 day Space Shuttle flight in June 1998. A proton background suppression on the order of 10^6 is reached by identifying converted bremsstrahlung photons emitted from positrons