Constraining Isocurvature Initial Conditions with WMAP 3-year data

We present constraints on the presence of isocurvature modes from the temperature and polarization CMB spectrum data from the WMAP satellite alone, and in combination with other datasets including SDSS galaxy survey and SNLS supernovae. We find that the inclusion of polarization data allows the WMAP data alone, as well as in combination with complementary observations, to place improved limits on the contribution of CDM and neutrino density isocurvature components individually. With general correlations, the upper limits on these sub-dominant isocurvature components are reduced to ~60% of the first year WMAP results, with specific limits depending on the type of fluctuations. If multiple isocurvature components are allowed, however, we find that the data still allow a majority of the initial power to come from isocurvature modes. As well as providing general constraints we also consider their interpretation in light of specific theoretical models like the curvaton and double inflation.Comment: 8 pages, 7 figures. Revised Sec 4 and Figs 3-4 post-publication to correct an error for models with varying isocurvature spectral inde

Fusing Continuous-valued Medical Labels using a Bayesian Model

With the rapid increase in volume of time series medical data available through wearable devices, there is a need to employ automated algorithms to label data. Examples of labels include interventions, changes in activity (e.g. sleep) and changes in physiology (e.g. arrhythmias). However, automated algorithms tend to be unreliable resulting in lower quality care. Expert annotations are scarce, expensive, and prone to significant inter- and intra-observer variance. To address these problems, a Bayesian Continuous-valued Label Aggregator(BCLA) is proposed to provide a reliable estimation of label aggregation while accurately infer the precision and bias of each algorithm. The BCLA was applied to QT interval (pro-arrhythmic indicator) estimation from the electrocardiogram using labels from the 2006 PhysioNet/Computing in Cardiology Challenge database. It was compared to the mean, median, and a previously proposed Expectation Maximization (EM) label aggregation approaches. While accurately predicting each labelling algorithm's bias and precision, the root-mean-square error of the BCLA was 11.78$\pm$0.63ms, significantly outperforming the best Challenge entry (15.37$\pm$2.13ms) as well as the EM, mean, and median voting strategies (14.76$\pm$0.52ms, 17.61$\pm$0.55ms, and 14.43$\pm$0.57ms respectively with $p<0.0001$)

iCosmo: an Interactive Cosmology Package

Aims: The interactive software package iCosmo, designed to perform cosmological calculations is described. Methods: iCosmo is a software package to perform interactive cosmological calculations for the low redshift universe. Computing distance measures, the matter power spectrum, and the growth factor is supported for any values of the cosmological parameters. It also computes derived observed quantities for several cosmological probes such as cosmic shear, baryon acoustic oscillations and type Ia supernovae. The associated errors for these observables can be derived for customised surveys, or for pre-set values corresponding to current or planned instruments. The code also allows for the calculation of cosmological forecasts with Fisher matrices which can be manipulated to combine different surveys and cosmological probes. The code is written in the IDL language and thus benefits from the convenient interactive features and scientific library available in this language. iCosmo can also be used as an engine to perform cosmological calculations in batch mode, and forms a convenient adaptive platform for the development of further cosmological modules. With its extensive documentation, it may also serve as a useful resource for teaching and for newcomers in the field of cosmology. Results: The iCosmo package is described with various examples and command sequences. The code is freely available with documentation at http://www.icosmo.org, along with an interactive web interface and is part of the Initiative for Cosmology, a common archive for cosmological resources.Comment: 6 pages including 2 tables and 4 figures. Accepted and published in Astronomy and Astrophysics. Public code and further resources available at http://www.icosmo.or

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 African Hospitalist Fellowship

The African Paediatric Fellowship Programme is rolling out a training course for newly qualified paediatricians to equip them with the leadership skills to function in complex general paediatric settings. The care of children in Africa carries its own unique demands, from the layering effects of multiple conditions through to establishing and sustaining services under severe resource constraints. This novel training concept aims to strengthen confidence and knowledge in areas that are not priorities during standard general paediatric training. The skills gained are considered of great relevance in assisting general paediatricians to achieve their full potential in their careers

How light can the lightest neutralino be?

In this talk we summarize previous work on mass bounds of a light neutralino in the Minimal Supersymmetric Standard Model. We show that without the GUT relation between the gaugino mass parameters M_1 and M_2, the mass of the lightest neutralino is essentially unconstrained by collider bounds and precision observables. We conclude by considering also the astrophysics and cosmology of a light neutralino.Comment: 6 pages, 3 figures, to appear in the proceedings of the 16th International Symposium on Particles, Strings and Cosmology (PASCOS2010), Valencia (Spain), July 19th - 23rd, 201

CMBPol Mission Concept Study: A Mission to Map our Origins

Quantum mechanical metric fluctuations during an early inflationary phase of the universe leave a characteristic imprint in the polarization of the cosmic microwave background (CMB). The amplitude of this signal depends on the energy scale at which inflation occurred. Detailed observations by a dedicated satellite mission (CMBPol) therefore provide information about energy scales as high as $10^{15}$ GeV, twelve orders of magnitude greater than the highest energies accessible to particle accelerators, and probe the earliest moments in the history of the universe. This summary provides an overview of a set of studies exploring the scientific payoff of CMBPol in diverse areas of modern cosmology, such as the physics of inflation, gravitational lensing and cosmic reionization, as well as foreground science and removal .Comment: 6 pages, 3 figure

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

SHRIMP U-Pb zircon geochronology of southern Madagascar: New evidence of Mesoarchaean crust and its implications on Madagascar tectonothermal history

第3回極域科学シンポジウム/第32回極域地学シンポジウム 11月30日（金） 統計数理研究所 ３階セミナー