A new approach to equipment testing

Considerable controversy has arisen during the recent discussions over a new version of the RTCA DO160C/ED 14C Section 22 document at the European Committee for Aviation Electronics. Section 22 is concerned with lightning waveform tests to equipment. Investigations of some of these controversies with circuit analysis and measurements indicate the impedance characteristics required of the transient generators and the possibility of testing to a voltage limit even for current waveforms

i-Tracker: For quantitative proteomics using iTRAQ (TM)

Background: iTRAQ(TM) technology for protein quantitation using mass spectrometry is a recent, powerful means of determining relative protein levels in up to four samples simultaneously. Although protein identification of samples generated using iTRAQ may be carried out using any current identification software, the quantitation calculations have been restricted to the ProQuant software supplied by Applied Biosciences. i- Tracker software has been developed to extract reporter ion peak ratios from non-centroided tandem MS peak lists in a format easily linked to the results of protein identification tools such as Mascot and Sequest. Such functionality is currently not provided by ProQuant, which is restricted to matching quantitative information to the peptide identifications from Applied Biosciences' Interrogator T software.|Results: i- Tracker is shown to generate results that are consistent with those produced by ProQuant, thus validating both systems.|Conclusion: i- Tracker allows quantitative information gained using the iTRAQ protocol to be linked with peptide identifications from popular tandem MS identification tools and hence is both a timely and useful tool for the proteomics community

Assumptions of the primordial spectrum and cosmological parameter estimation

The observables of the perturbed universe, CMB anisotropy and large structures, depend on a set of cosmological parameters, as well as, the assumed nature of primordial perturbations. In particular, the shape of the primordial power spectrum (PPS) is, at best, a well motivated assumption. It is known that the assumed functional form of the PPS in cosmological parameter estimation can affect the best fit parameters and their relative confidence limits. In this paper, we demonstrate that a specific assumed form actually drives the best fit parameters into distinct basins of likelihood in the space of cosmological parameters where the likelihood resists improvement via modifications to the PPS. The regions where considerably better likelihoods are obtained allowing free form PPS lie outside these basins. In the absence of a preferred model of inflation, this raises a concern that current cosmological parameters estimates are strongly prejudiced by the assumed form of PPS. Our results strongly motivate approaches toward simultaneous estimation of the cosmological parameters and the shape of the primordial spectrum from upcoming cosmological data. It is equally important for theorists to keep an open mind towards early universe scenarios that produce features in the PPS.Comment: 11 pages, 2 figures, discussions extended, main results unchanged, matches published versio

The initial conditions of the universe: how much isocurvature is allowed?

We investigate the constraints imposed by the current data on correlated mixtures of adiabatic and non-adiabatic primordial perturbations. We discover subtle flat directions in parameter space that tolerate large (~60%) contributions of non-adiabatic fluctuations. In particular, larger values of the baryon density and a spectral tilt are allowed. The cancellations in the degenerate directions are explored and the role of priors elucidated.Comment: 4 pages, 4 figures. Submitted to PR

Constraints on isocurvature models from the WMAP first-year data

We investigate the constraints imposed by the first-year WMAP CMB data extended to higher multipole by data from ACBAR, BOOMERANG, CBI and the VSA and by the LSS data from the 2dF galaxy redshift survey on the possible amplitude of primordial isocurvature modes. A flat universe with CDM and Lambda is assumed, and the baryon, CDM (CI), and neutrino density (NID) and velocity (NIV) isocurvature modes are considered. Constraints on the allowed isocurvature contributions are established from the data for various combinations of the adiabatic mode and one, two, and three isocurvature modes, with intermode cross-correlations allowed. Since baryon and CDM isocurvature are observationally virtually indistinguishable, these modes are not considered separately. We find that when just a single isocurvature mode is added, the present data allows an isocurvature fraction as large as 13+-6, 7+-4, and 13+-7 percent for adiabatic plus the CI, NID, and NIV modes, respectively. When two isocurvature modes plus the adiabatic mode and cross-correlations are allowed, these percentages rise to 47+-16, 34+-12, and 44+-12 for the combinations CI+NID, CI+NIV, and NID+NIV, respectively. Finally, when all three isocurvature modes and cross-correlations are allowed, the admissible isocurvature fraction rises to 57+-9 per cent. The sensitivity of the results to the choice of prior probability distribution is examined.Comment: 20 pages, 24 figures. Submitted to PR

Peaks in the cosmological density field: parameter constraints from 2dF Galaxy Redshift Survey data

We use the number density of peaks in the smoothed cosmological density field taken from the 2dF Galaxy Redshift Survey to constrain parameters related to the power spectrum of mass fluctuations, n (the spectral index), dn/d(lnk) (rolling in the spectral index), and the neutrino mass, m_nu. In a companion paper we use N-body simulations to study how the peak density responds to changes in the power spectrum, the presence of redshift distortions and the relationship between galaxies and dark matter halos. In the present paper we make measurements of the peak density from 2dF Galaxy Redshift Survey data, for a range of smoothing filter scales from 4-33 h^-1 Mpc. We use these measurements to constrain the cosmological parameters, finding n=1.36 (+0.75)(-0.64), m_nu < 1.76 eV, dn/d(lnk)=-0.012 (+0.192)(-0.208), at the 68 % confidence level, where m_nu is the total mass of three massive neutrinos. At 95% confidence we find m_nu< 2.48 eV. These measurements represent an alternative way to constrain cosmological parameters to the usual direct fits to the galaxy power spectrum, and are expected to be relatively insensitive to non-linear clustering evolution and galaxy biasing.Comment: Accepted for Publication in MNRAS on Sept 25, 2009. Abstract modified to remove LaTex markup

Turbulence and turbulent mixing in natural fluids

Turbulence and turbulent mixing in natural fluids begins with big bang turbulence powered by spinning combustible combinations of Planck particles and Planck antiparticles. Particle prograde accretions on a spinning pair releases 42% of the particle rest mass energy to produce more fuel for turbulent combustion. Negative viscous stresses and negative turbulence stresses work against gravity, extracting mass-energy and space-time from the vacuum. Turbulence mixes cooling temperatures until strong-force viscous stresses freeze out turbulent mixing patterns as the first fossil turbulence. Cosmic microwave background temperature anisotropies show big bang turbulence fossils along with fossils of weak plasma turbulence triggered as plasma photon-viscous forces permit gravitational fragmentation on supercluster to galaxy mass scales. Turbulent morphologies and viscous-turbulent lengths appear as linear gas-proto-galaxy-clusters in the Hubble ultra-deep-field at z~7. Proto-galaxies fragment into Jeans-mass-clumps of primordial-gas-planets at decoupling: the dark matter of galaxies. Shortly after the plasma to gas transition, planet-mergers produce stars that explode on overfeeding to fertilize and distribute the first life.Comment: 23 pages 12 figures, Turbulent Mixing and Beyond 2009 International Center for Theoretical Physics conference, Trieste, Italy. Revision according to Referee comments. Accepted for Physica Scripta Topical Issue to be published in 201

Maximum likelihood, parametric component separation and CMB B-mode detection in suborbital experiments

We investigate the performance of the parametric Maximum Likelihood component separation method in the context of the CMB B-mode signal detection and its characterization by small-scale CMB suborbital experiments. We consider high-resolution (FWHM=8') balloon-borne and ground-based observatories mapping low dust-contrast sky areas of 400 and 1000 square degrees, in three frequency channels, 150, 250, 410 GHz, and 90, 150, 220 GHz, with sensitivity of order 1 to 10 micro-K per beam-size pixel. These are chosen to be representative of some of the proposed, next-generation, bolometric experiments. We study the residual foreground contributions left in the recovered CMB maps in the pixel and harmonic domain and discuss their impact on a determination of the tensor-to-scalar ratio, r. In particular, we find that the residuals derived from the simulated data of the considered balloon-borne observatories are sufficiently low not to be relevant for the B-mode science. However, the ground-based observatories are in need of some external information to permit satisfactory cleaning. We find that if such information is indeed available in the latter case, both the ground-based and balloon-borne experiments can detect the values of r as low as ~0.04 at 95% confidence level. The contribution of the foreground residuals to these limits is found to be then subdominant and these are driven by the statistical uncertainty due to CMB, including E-to-B leakage, and noise. We emphasize that reaching such levels will require a sufficient control of the level of systematic effects present in the data.Comment: 18 pages, 12 figures, 6 table

Integrated care for childhood epilepsy: ongoing challenges and lessons for other long-term conditions

Epilepsy care has been identified as a major global issue – and there are many recognised concerns in the UK for children and young people with the condition. A proposed new model could help to increase multi-sector integration, facilitate better outcomes, and offer lessons for improving care of other long-term conditions

Impact of Systematics on SZ-Optical Scaling Relations

One of the central goals of multi-wavelength galaxy cluster cosmology is to unite all cluster observables to form a consistent understanding of cluster mass. Here, we study the impact of systematic effects from optical cluster catalogs on stacked SZ signals. We show that the optically predicted Y-decrement can vary by as much as 50% based on the current 2 sigma systematic uncertainties in the observed mass-richness relationship. Mis-centering and impurities will suppress the SZ signal compared to expectations for a clean and perfectly centered optical sample, but to a lesser degree. We show that the level of these variations and suppression is dependent on the amount of systematics in the optical cluster catalogs. We also study X-ray luminosity-dependent sub-sampling of the optical catalog and find that it creates Malmquist bias increasing the observed Y-decrement of the stacked signal. We show that the current Planck measurements of the Y-decrement around SDSS optical clusters and their X-ray counterparts are consistent with expectations after accounting for the 1 sigma optical systematic uncertainties using the Johnston mass richness relation.Comment: 6 pages, 4 figures. Revised to match version accepted in the Astrophysical Journa