Principal Components of CMB non-Gaussianity

The skew-spectrum statistic introduced by Munshi & Heavens (2010) has recently been used in studies of non-Gaussianity from diverse cosmological data sets including the detection of primary and secondary non-Gaussianity of Cosmic Microwave Background (CMB) radiation. Extending previous work, focussed on independent estimation, here we deal with the question of joint estimation of multiple skew-spectra from the same or correlated data sets. We consider the optimum skew-spectra for various models of primordial non-Gaussianity as well as secondary bispectra that originate from the cross-correlation of secondaries and lensing of CMB: coupling of lensing with the Integrated Sachs-Wolfe (ISW) effect, coupling of lensing with thermal Sunyaev-Zeldovich (tSZ), as well as from unresolved point-sources (PS). For joint estimation of various types of non-Gaussianity, we use the PCA to construct the linear combinations of amplitudes of various models of non-Gaussianity, e.g. $f^{\rm loc}_{\rm NL},f^{\rm eq}_{\rm NL},f^{\rm ortho}_{\rm NL}$ that can be estimated from CMB maps. Bias induced in the estimation of primordial non-Gaussianity due to secondary non-Gaussianity is evaluated. The PCA approach allows one to infer approximate (but generally accurate) constraints using CMB data sets on any reasonably smooth model by use of a lookup table and performing a simple computation. This principle is validated by computing constraints on the DBI bispectrum using a PCA analysis of the standard templates.Comment: 17 pages, 5 figures, 4 tables. Matches published versio

Consistency Relations in Effective Field Theory

The consistency relations in large scale structure relate the lower-order correlation functions with their higher-order counterparts. They are direct outcome of the underlying symmetries of a dynamical system and can be tested using data from future surveys such as Euclid. Using techniques from standard perturbation theory (SPT), previous studies of consistency relation have concentrated on continuity-momentum (Euler)-Poisson system of an ideal fluid. We investigate the consistency relations in effective field theory (EFT) which adjusts the SPT predictions to account for the departure from the ideal fluid description on small scales. We provide detailed results for the 3D density contrast $\delta$ as well as the {\em scaled} divergence of velocity $\bar\theta$. Assuming a $\Lambda$CDM background cosmology, we find the correction to SPT results becomes important at $k \gtrsim 0.05 \rm h/Mpc$ and that the suppression from EFT to SPT results that scales as square of the wave number $k$, can reach $40\%$ of the total at $k \approx 0.25\rm h/Mpc$ at $z=0$. We have also investigated whether effective field theory corrections to models of primordial non-Gaussianity can alter the squeezed limit behaviour, finding the results to be rather insensitive to these counterterms. In addition, we present the EFT corrections to the squeezed limit of the bispectrum in redshift space which may be of interest for tests of theories of modified gravity.Comment: 23 pages + bibliography, 6 figures. Minor changes to match version accepted for publication by JCA

General CMB bispectrum analysis using wavelets and separable modes

In this paper we combine partial-wave (`modal') methods with a wavelet analysis of the CMB bispectrum. Our implementation exploits the advantages of both approaches to produce robust, reliable and efficient estimators which can constrain the amplitude of arbitrary primordial bispectra. This will be particularly important for upcoming surveys such as \emph{Planck}. A key advantage is the computational efficiency of calculating the inverse covariance matrix in wavelet space, producing an error bar which is close to optimal. We verify the efficacy and robustness of the method by applying it to WMAP7 data, finding \fnllocal=38.4 \pm 23.6 and \fnlequil=-119.2 \pm 123.6

Voices of low SES women overcoming breastfeeding barriers: A qualitative analysis and model development

Abstract Background: Breast milk provides optimal nutrition for most infants for a specific amount of time. In spite of well-accepted benefits associated with breastfeeding, both for infants and mothers, rates among low-income women remain consistently low. Objective: The objective of this study was to identify what motivates women, who are at a high risk of not initiating breastfeeding or early weaning, to establish a successful breastfeeding relationship. Methods: Mothers meeting the eligibility criteria of having no more than a high school degree, being low-income, and having breastfed for \u3e 3 weeks, completed an in-depth telephone interview. Using grounded-theory methodology, researchers developed a theoretical model describing the experience of this population. Results: Though recruitment was ongoing for over a year, with 212 mothers screened for eligibility, only seven mothers were eligible and completed study activities. Based on analysis of interview transcripts, a theoretical model was developed. Conclusions: Mothers who breastfeed despite being high-risk for not breastfeeding may be motivated by the perception that breastfeeding is easier than formula feeding and comforting. In addition, the breastfeeding relationship may be protected by the services offered by WIC, which may be amplified by the mother’s own determination. A lack of experienced barriers and the act of bed-sharing may also assist with breastfeeding duration. The researchers hypothesize that, as barriers are experienced that are beyond the perceived control of WIC services, the mother’s level of stress may increase, increasing the likelihood of weaning. Future research should test the proposed model and determine specific messages targeting this at-risk population

Rose of the World

https://digitalcommons.library.umaine.edu/mmb-vp/6141/thumbnail.jp

Ultrasonic measurement of core material temperature, phase 1

High temperature ultrasonic temperature measurements in nuclear rocket engine to determine feasibility of rhenium sensor as high temperature senso

Ultrasonic measurement of core material temperature, phase 2

Sheaths for pulse-echo ultrasonic temperature senso

Design of a memory based expert system for interpreting facial expressions in terms of signalled emotions

A memory based expert system(JANUS) has been designed to interpret facial expression in terms of the signalled emotion. Janus accepts a geometric description of the face obtained from measurements on a digitised full face photograph and returns the appropriate emotion label. An intermediate representation in terms of verbal face actions(eg. . mouth open,eyes closed)is also used. A production rule system converts the geometric description to verbal form, while a dynamic memory interprets the face actions in terms of emotions. Following the work of Schank(1982)and Kolodner (1984),the dynamic memory is structured as a tree of packets, storing, in Janus, typical facial expressions connected by links to atypical but related face expressions previously encountered. This enables new input to be channelled along the appropriate path to an interpretation based on previous experience. The system is capable of learning new emotion labels and associated face actions for use in subsequent interpretations. A prototype system has been developed on a SUN 2/MJN/120 system using POPLOG.V alidation studies suggest that the interpretations offered by Janus are generally consistent with those of human expert

Never Mind, Bopeep, We Will Find Your Sheep

https://digitalcommons.library.umaine.edu/mmb-vp/5533/thumbnail.jp