This paper describes the work carried out in the RACE Project R2039 ATMOS (asynchronous transfer mode optical switching). The project is briefly illustrated, together with its main goal: to develop ...and assess concepts and technology suitable for optical fast packet switching. The project's technical approach consisted in the exploitation of the space and wavelength domains for fast routing and buffering: The major achievements are then reported. Four different switch architecture concepts have been proposed, investigated and developed, all based on a high speed optical routing matrix electrically controlled at lower speed. The basic optical key components and subsystems (wavelength converters, space switches and optical buffers) are described in detail, with the outstanding results obtained and the corresponding projected performance. In particular, system demonstration of wavelength conversion at 10 and 20 Gb/s has been realized, to show the usefulness of the ATMOS technology both to implement optimized high performance optical packet-switching fabrics as well as transparent optical circuit-routing nodes. Four rack-mounted, reduced size demonstrators of basic switching matrices have been designed and implemented scalable to real system sizes. The obtained good results in terms of bit error rate and hardware integration are reported, showing that ATM switches are feasible with state of-the-art optical technology.
Sleep apnea (SA) is associated with cardiovascular diseases and is highly prevalent in patients with pacemakers (PMs).
To validate a transthoracic impedance sensor with an advanced algorithm (sleep ...apnea monitoring) for identifying severe SA.
Patients with indications for PM (VVI/DDD) were enrolled regardless of symptoms suggesting SA. Severe SA diagnosis was acknowledged when the full polysomnography gave an apnea-hypopnea index (PSG-AHI) of ≥30 events/h. The PSG-AHI was compared with the respiratory disturbance index evaluated by the SAM algorithm (SAM-RDI) compiled from the device during the same diagnosis night, and the performance of the device and the SAM algorithm was calculated to identify patients with severe SA. The agreement between methods was assessed by using Bland and Altman statistics.
Forty patients (mean age 73.8 ± 19.1 years; 67.5% men; body mass index 27.7 ± 4.4 kg/m2) were included. Severe SA was diagnosed by PSG in 56% of the patients. We did not retrieve SAM-RDI data in 14% of the patients. An optimal cutoff value for the SAM-RDI at 20 events/h was obtained by a receiver operator characteristic curve analysis, which yielded a sensitivity of 88.9% (95% confidence interval CI 65.3%–98.6%), a positive predictive value of 88.9% (95% CI 65.3%–98.6%), and a specificity of 84.6% (95% CI 54.6%–98.1%) (n = 31). The Bland-Altman limits of agreement for PSG-AHI (in events per hour) were −14.1 to 32.4.
The results suggest that an advanced algorithm using PM transthoracic impedance could be used to identify SA in patients with PMs outside the clinic or at home.
Aims. The previously unidentified very high-energy (VHE; E > 100 GeV) γ-ray source HESS J1303−631, discovered in 2004, is re-examined including new data from the H.E.S.S. Cherenkov telescope array in ...order to identify this object. Archival data from the XMM-Newton X-ray satellite and from the PMN radio survey are also examined. Methods. Detailed morphological and spectral studies of VHE γ-ray emission as well as of the XMM-Newton X-ray data are performed. Radio data from the PMN survey are used as well to construct a leptonic model of the source. The γ-ray and X-ray spectra and radio upper limit are used to construct a one zone leptonic model of the spectral energy distribution (SED). Results. Significant energy-dependent morphology of the γ-ray source is detected with high-energy emission (E > 10 TeV) positionally coincident with the pulsar PSR J1301−6305 and lower energy emission (E < 2 TeV) extending ~0.4° to the southeast of the pulsar. The spectrum of the VHE source can be described with a power-law with an exponential cut-off N0 = (5.6 ± 0.5) × 10-12 TeV-1 cm-2 s-1, Γ = 1.5 ± 0.2) and Ecut = (7.7 ± 2.2) TeV. The pulsar wind nebula (PWN) is also detected in X-rays, extending ~2−3′ from the pulsar position towards the center of the γ-ray emission region. A potential radio counterpart from the PMN survey is also discussed, showing a hint for a counterpart at the edge of the X-ray PWN trail and is taken as an upper limit in the SED. The extended X-ray PWN has an unabsorbed flux of \hbox{$F_{\rm 2{-}10~keV} \sim 1.6^{+0.2}_{-0.4}\times 10^{-13}\textrm{~erg\,cm}^{-2}\textrm{\,s}^{-1}$}F2−10 keV~1.6-0.4+0.2×10-13 erg cm-2 s-1 and is detected at a significance of 6.5σ. The SED is well described by a one zone leptonic scenario which, with its associated caveats, predicts a very low average magnetic field for this source. Conclusions. Significant energy-dependent morphology of this source, as well as the identification of an associated X-ray PWN from XMM-Newton observations enable identification of the VHE source as an evolved PWN associated to the pulsar PSR J1301−6305. This identification is supported by the one zone leptonic model, which suggests that the energetics of the γ-ray and X-ray radiation are such that they may have a similar origin in the pulsar nebula. However, the large discrepancy in emission region sizes and the low level of synchrotron radiation suggest a multi-population leptonic nature. The low implied magnetic field suggests that the PWN has undergone significant expansion. This would explain the low level of synchrotron radiation and the difficulty in detecting counterparts at lower energies, the reason this source was originally classified as a “dark” VHE γ-ray source.
Very high-energy γ-ray emission from PKS 0447−439 was detected with the H.E.S.S. Cherenkov telescope array in December 2009. This blazar is one of the brightest extragalactic objects in the Fermi ...bright source list and has a hard spectrum in the MeV to GeV range. In the TeV range, a photon index of 3.89 ± 0.37 (stat) ±0.22 (sys) and a flux normalisation at 1 TeV, Φ1 TeV = (3.5 ± 1.1(stat) ± 0.9(sys)) × 10-13 cm-2 s-1 TeV-1 were found. The detection with H.E.S.S. triggered observations in the X-ray band with the Swift and RXTE telescopes. Simultaneous UV and optical data from Swift UVOT and data from the optical telescopes ATOM and ROTSE are also available. The spectrum and light curve measured with H.E.S.S. are presented and compared to the multi-wavelength data at lower energies. A rapid flare is seen in the Swift XRT and RXTE data, together with a flux variation in the UV band, at a time scale of the order of one day. A firm upper limit of z < 0.59 on the redshift of PKS 0447−439 is derived from the combined Fermi-LAT and H.E.S.S. data, given the assumptions that there is no upturn in the intrinsic spectrum above the Fermi-LAT energy range and that absorption on the extragalactic background light (EBL) is not weaker than the lower limit provided by current models. The spectral energy distribution is well described by a simple one-zone synchrotron self-Compton scenario, if the redshift of the source is less than z ≲ 0.4.
Objective We sought to evaluate the efficacy of maternal posturing during labor on the prevention of persistent occiput posterior (OP) position. Study Design We conducted a randomized trial including ...220 patients in labor with a single fetus in documented OP position. Main outcome was the proportion of anterior rotation from OP position. Results The rates of anterior rotation were, respectively, 78.2% and 76.4% in the intervention group and the control group without significant difference ( P = .748). Rates of instrumental and cesarean section deliveries were not significantly different between intervention and control groups (18.2% vs 19.1%, P = .89, and 19.1% vs 17.3%, P = .73, respectively). In intervention and control groups, persistent OP position rates were significantly higher among women who had cesarean section (71.4% and 89.5%, respectively) and an instrumental delivery (25% and 33.3%, respectively) than among women who achieved spontaneous vaginal birth (5.8% and 2.8%, respectively). In multivariable analysis, body mass index and parity were found to have significant and independent impact on the probability of fetal head rotation. Conclusion Our study failed to demonstrate any maternal or neonatal benefit to a policy of maternal posturing for the management of OP position during labor.
Several young supernova remnants (SNR) have recently been detected in the high-energy and very-high-energy gamma-ray domains. As exemplified by RX J1713.7-3946, the nature of this emission has been ...hotly debated, and direct evidence for the efficient acceleration of cosmic-ray protons at the SNR shocks still remains elusive. The authors study the broadband gamma-ray emission from one of these young SNRs, namely RCW86, for which several observational lines of evidence indirectly point towards the presence of accelerated hadrons. They analyzed more than 40 months of data acquired by the Large Area Telescope on-board the Fermi Gamma-Ray Space Telescope in the HE domain, and gathered all of the relevant multi-wavelength information about the broadband nonthermal emission from RCW86. For this purpose, the authors re-analyzed the archival X-ray data from the ASCA/Gas Imaging Spectrometer, the XMM-Newton/EPIC-MOS, and the RXTE/Proportional Counter Array. Beyond the expected Galactic diffuse background, no significant gamma-ray emission in the direction of RCW86 is detected in any of the 0.1-1, 1-10 and 10-100 GeV Fermi-LAT maps.
We experimentally investigate a pass-through scheme for all-optical noise suppression in a SOA-based interferometric structure at 10 Gb/s. An input power dynamic range of /spl sim/8 dB as well as a ...noise suppression capability of /spl sim/4.5 dB has been demonstrated. Furthermore, the transmission properties have been investigated showing a small pre-amplified penalty of /spl sim/0.3 dB after transmission over 31 km of standard single mode fiber.
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