The Virgo gravitational wave detector is an interferometer (ITF) with 3km
arms located in Pisa, Italy. From July to October 2010, Virgo performed its
third science run (VSR3) in coincidence with the ...LIGO detectors. Despite
several techniques adopted to isolate the interferometer from the environment,
seismic noise remains an important issue for Virgo. Vibrations produced by the
detector infrastructure (such as air conditioning units, water
chillers/heaters, pumps) are found to affect Virgo's sensitivity, with the main
coupling mechanisms being through beam jitter and scattered light processes.
The Advanced Virgo (AdV) design seeks to reduce ITF couplings to environmental
noise by having most vibration-sensitive components suspended and in-vacuum, as
well as muffle and relocate loud machines. During the months of June and July
2010, a Guralp-3TD seismometer was stationed at various locations around the
Virgo site hosting major infrastructure machines. Seismic data were examined
using spectral and coherence analysis with seismic probes close to the
detector. The primary aim of this study was to identify noisy machines which
seismically affect the ITF environment and thus require mitigation attention.
Analyzed machines are located at various distances from the experimental halls,
ranging from 10m to 100m. An attempt is made to measure the attenuation of
emitted noise at the ITF and correlate it to the distance from the source and
to seismic attenuation models in soil.
A novel method is proposed for a laboratory test of the time independence of the fine-structure constant and of the electron to proton mass ratio, employing only electromagnetic resonators. For a ...resonator made out of a dielectric ionic or molecular crystal, the resonance frequencies depend on the product {alpha}{sup 2}m{sub e}/m{sub p} through the index of refraction. A test of the time independence of {alpha} and m{sub e}/m{sub p} can be performed by a search for a long-term change in the difference of two resonance frequencies exhibiting different dispersion. The method can be advantageously implemented with a single resonator. The prospects of implementation using optical resonators, systematic effects, and experimental requirements for a test at the level of 4 x 10{sup -15}/yr relative variation in {alpha} or m{sub e}/m{sub p} are discussed. On the experimental side, birefringent monolithic sapphire optical resonators with high-reflectivity mirrors are fabricated and characterized. The measurements of optical materials with ultralow absorption loss (ppm/cm level), required for the proposed method, are also reported.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Therapeutic control of HIV replication reduces the size of the viral reservoir, particularly among central memory CD4+ T cells, and this effect might be accentuated by early treatment.
We examined ...the effect of ART initiated at the time of the primary HIV infection (early ART), lasting 2 and 6 years in 11 and 10 patients, respectively, on the HIV reservoir in peripheral resting CD4+ T cells, sorted into naive (TN), central memory (TCM), transitional memory (TTM) and effector memory (TEM) cells, by comparison with 11 post-treatment controllers (PTCs).
Between baseline and 2 years, CD4+ T cell subset numbers increased markedly (P < 0.004) and HIV DNA levels decreased in all subsets (P < 0.009). TTM cells represented the majority of reservoir cells at both timepoints, T cell activation status normalized and viral diversity remained stable over time. The HIV reservoir was smaller after 6 years of early ART than after 2 years (P < 0.019), and did not differ between PTCs and patients treated for 6 years. One patient, who had low reservoir levels in all T cell subsets after 2 years of treatment similar to the levels in PTCs, spontaneously controlled viral replication during 18 months off treatment.
Early prolonged ART thus limits the size of the HIV reservoir, protects long-lived cells from persistent infection and may enhance post-treatment control.
The gravitational wave detector VIRGO aims at extending the detection band down to a few Hertz by isolating the mirrors of the interferometer from seismic noise. This result is achieved by hanging ...each mirror through an elastic suspension (Superattenuator), designed to filter mechanical vibrations in all the degrees of freedom. An experimental upper limit of the mirror residual seismic noise at a few Hertz is provided in this paper. This is lower than the thermal noise floor, expected to limit the antenna sensitivity in the low frequency range.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
30.
Status of Virgo Amico, P; Al-Shourbagy, M; Avino, S ...
Classical and quantum gravity,
09/2005, Volume:
22, Issue:
18
Journal Article, Conference Proceeding
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