A Solid State Pulsed Coagulating Diathermy Instrument

Solid state pulsed coagulating diathermy instrumen

Sensitivity of Space Station alpha joint robust controller to structural modal parameter variations

The photovoltaic array sun tracking control system of Space Station Freedom is described. A synthesis procedure for determining optimized values of the design variables of the control system is developed using a constrained optimization technique. The synthesis is performed to provide a given level of stability margin, to achieve the most responsive tracking performance, and to meet other design requirements. Performance of the baseline design, which is synthesized using predicted structural characteristics, is discussed and the sensitivity of the stability margin is examined for variations of the frequencies, mode shapes and damping ratios of dominant structural modes. The design provides enough robustness to tolerate a sizeable error in the predicted modal parameters. A study was made of the sensitivity of performance indicators as the modal parameters of the dominant modes vary. The design variables are resynthesized for varying modal parameters in order to achieve the most responsive tracking performance while satisfying the design requirements. This procedure of reoptimization design parameters would be useful in improving the control system performance if accurate model data are provided

Quantum random number generation for 1.25 GHz quantum key distribution systems

Security proofs of quantum key distribution (QKD) systems usually assume that the users have access to source of perfect randomness. State-of-the-art QKD systems run at frequencies in the GHz range, requiring a sustained GHz rate of generation and acquisition of quantum random numbers. In this paper we demonstrate such a high speed random number generator. The entropy source is based on amplified spontaneous emission from an erbium-doped fibre, which is directly acquired using a standard small form-factor pluggable (SFP) module. The module connects to the Field Programmable Gate Array (FPGA) of a QKD system. A real-time randomness extractor is implemented in the FPGA and achieves a sustained rate of 1.25 Gbps of provably random bits.Comment: 6 pages, 8 figure

Genome-wide DNA hypomethylation and RNA:DNA hybrid accumulation in Aicardi-Goutières syndrome.

Aicardi-Goutières syndrome (AGS) is a severe childhood inflammatory disorder that shows clinical and genetic overlap with systemic lupus erythematosus (SLE). AGS is thought to arise from the accumulation of incompletely metabolized endogenous nucleic acid species owing to mutations in nucleic acid-degrading enzymes TREX1 (AGS1), RNase H2 (AGS2, 3 and 4), and SAMHD1 (AGS5). However, the identity and source of such immunogenic nucleic acid species remain undefined. Using genome-wide approaches, we show that fibroblasts from AGS patients with AGS1-5 mutations are burdened by excessive loads of RNA:DNA hybrids. Using MethylC-seq, we show that AGS fibroblasts display pronounced and global loss of DNA methylation and demonstrate that AGS-specific RNA:DNA hybrids often occur within DNA hypomethylated regions. Altogether, our data suggest that RNA:DNA hybrids may represent a common immunogenic form of nucleic acids in AGS and provide the first evidence of epigenetic perturbations in AGS, furthering the links between AGS and SLE

Can We See Lorentz-Violating Vector Fields in the CMB?

We investigate the perturbation theory of a fixed-norm, timelike Lorentz-violating vector field. After consistently quantizing the vector field to put constraints on its parameters, we compute the primordial spectra of perturbations generated by inflation in the presence of this vector field. We find that its perturbations are sourced by the perturbations of the inflaton; without the inflaton perturbation the vector field perturbations decay away leaving no primordial spectra of perturbations. Since the inflaton perturbation does not have a spin-1 component, the vector field generically does not generate any spin-1 ``vector-type'' perturbations. Nevertheless, it will modify the amplitude of both the spin-0 ``scalar-type'' and spin-2 ``tensor-type'' perturbation spectra, leading to violations of the inflationary consistency relationship.Comment: 36 pages, 1 fig, RevTex4, Submitted to PR

Unexpected phase locking of magnetic fluctuations in the multi-k magnet USb

The spin waves in the multi-k antiferromagnet USb soften and become quasielastic well below the antiferromagnetic ordering temperature TN. This occurs without a magnetic or structural transition. It has been suggested that this change is in fact due to dephasing of the different multi-k components: a switch from 3-k to 1-k behavior. In this work, we use inelastic neutron scattering with tridirectional polarization analysis to probe the quasielastic magnetic excitations and reveal that the 3-k structure does not dephase. More surprisingly, the paramagnetic correlations also maintain the same clear phase correlations well above TN (up to at least 1.4TN)