Scheme Independence to all Loops

The immense freedom in the construction of Exact Renormalization Groups means that the many non-universal details of the formalism need never be exactly specified, instead satisfying only general constraints. In the context of a manifestly gauge invariant Exact Renormalization Group for SU(N) Yang-Mills, we outline a proof that, to all orders in perturbation theory, all explicit dependence of beta function coefficients on both the seed action and details of the covariantization cancels out. Further, we speculate that, within the infinite number of renormalization schemes implicit within our approach, the perturbative beta function depends only on the universal details of the setup, to all orders.Comment: 18 pages, 8 figures; Proceedings of Renormalization Group 2005, Helsinki, Finland, 30th August - 3 September 2005. v2: Published in jphysa; minor changes / refinements; refs. adde

Frequency shifting with a solid-state switching capacitor

Frequency shifting, commonly used in electronic signal processing, is applied in tuning, automatic frequency control, antenna element switching, phase shifting, etc. Frequency shifting can be accomplished economically and reliably with simple circuit comprising conventional resistor and solid-state switching device which can be equivalent to two capacitors, depending on switching state

The Birmingham-CfA cluster scaling project - II. Mass composition and distribution

We investigate the spatial distribution of the baryonic and non-baryonic mass components in a sample of 66 virialized systems. We have used X-ray measurements to determine the deprojected temperature and density structure of the intergalactic medium and have employed these to map the underlying gravitational potential. In addition, we have measured the deprojected spatial distribution of galaxy luminosity for a subset of this sample, spanning over 2 decades in mass. With this combined X-ray/optical study we examine the scaling properties of the baryons and address the issue of mass-to-light (M/L) ratio in groups and clusters of galaxies. We measure a median mass-to-light ratio of 224 h70 M/L (solar) in the rest frame B_j band, in good agreement with other measurements based on X-ray determined masses. There is no trend in M/L with X-ray temperature and no significant trend for mass to increase faster than luminosity: M \propto \L_{B,j}^{1.08 +/- 0.12}. This implied lack of significant variation in star formation efficiency suggests that gas cooling cannot be greatly enhanced in groups, unless it drops out to form baryonic dark matter. Correspondingly, our results indicate that non-gravitational heating must have played a significant role in establishing the observed departure from self-similarity in low mass systems. The median baryon fraction for our sample is 0.162 h70^{-3/2}, which allows us to place an upper limit on the cosmological matter density, Omega_m <= 0.27 h70^{-1}, in good agreement with the latest results from WMAP. We find evidence of a systematic trend towards higher central density concentration in the coolest haloes, indicative of an early formation epoch and consistent with hierarchical formation models.Comment: 14 pages, 11 figures; published in MNRAS. Corrected mistake in photometric conversion (equation 2): Bj luminosities increased for A2218, N2563 & N5846. Conclusions unchange

Multi-Frequency Synthesis of VLBI Images Using a Generalized Maximum Entropy Method

A new multi-frequency synthesis algorithm for reconstructing images from multi-frequency VLBI data is proposed. The algorithm is based on a generalized maximum-entropy method, and makes it possible to derive an effective spectral correction for images over a broad frequency bandwidth, while simultaneously reconstructing the spectral-index distribution over the source. The results of numerical simulations demonstrating the capabilities of the algorithm are presented.Comment: 17 pages, 8 figure

Composite metal-oxide device has voltage sensitive capacitance

Device with step function variation of the capacitance is useful for voltage-controlled oscillator circuits and as a voltage-sensitive switch. Simplicity of construction makes the device suitable for large-scale integration, microelectronic circuits

Method of preparing water purification membranes

Allyl amine and chemically related compounds are polymerized as thin films in the presence of a plasma discharge. The monomer compound can be polymerized by itself or in the presence of an additive gas to promote polymerization and act as a carrier. The polymerized films thus produced show outstanding advantages when used as reverse osmosis membranes

Gas low pressure low flow rate metering system Patent

Flowmeters for sensing low fluid flow rate and pressure for application to respiration rate studie