Cosmology from cross correlation of CMB lensing and galaxy surveys

In recent years cross correlation of lensing of the Cosmic Microwave Background (CMB) with other large scale structure (LSS) tracers has been used as a method to detect CMB lensing. Current experiments are also becoming sensitive enough to measure CMB lensing without the help of auxiliary tracers. As data quality improves rapidly, it has been suggested that the CMB lensing-LSS cross correlation may provide new insights into parameters describing cosmological structure growth. In this work we perform forecasts that combine the lensing potential auto power spectrum from various future CMB experiments, the galaxy power spectrum from galaxy surveys, as well as the cross power spectrum between the two, marginalizing over a number galactic and non-galactic cosmological parameters. We find that the CMB lensing-LSS cross correlation contains significant information on parameters such as the redshift distribution and bias of LSS tracers. We also find that the cross correlation information will lead to independent probes of cosmological parameters such as neutrino mass and the reionization optical depth.Comment: 9 pages, 5 figure

CMB lensing reconstruction using cut sky polarization maps and pure B modes

Detailed measurements of the CMB lensing signal are an important scientific goal of ongoing groundbased CMB polarization experiments, which are mapping the CMB at high resolution over small patches of the sky. In this work we simulate CMB polarization lensing reconstruction for the EE and EB quadratic estimators with current-generation noise levels and resolution, and show that without boundary effects the known and expected zeroth and first order Nð0Þ and Nð1Þ biases provide an adequate model for nonsignal contributions to the lensing power spectrum estimators. Small sky areas present a number of additional challenges for polarization lensing reconstruction, including leakage of E modes into B modes. We show how simple windowed estimators using filtered pure B modes can greatly reduce the mask-induced meanfield lensing signal and reduce variance in the estimators. This provides a simple method (used with recent observations) that gives an alternative to more optimal but expensive inverse-variance filtering

LSE RB feature: Sundari Anitha and Ruth Pearson introduce striking women: struggles and strategies of South Asian women workers from Grunwick to Gate Gourmet

In this feature essay, Sundari Anitha and Ruth Pearson introduce their new book, Striking Women: Struggles and Strategies of South Asian Women Workers from Grunwick to Gate Gourmet, which focuses on two industrial disputes in the UK: the famous Grunwick strike (1976-78) and the Gate Gourmet dispute of 2005. The book, which is being launched at SOAS, University of London, on Thursday 26 April 2018, gives a voice to the women involved in the strikes and explores South Asian women’s contribution to the struggles for worker’s rights in Britain. If you are interested in this book, you may also want to visit the interactive website www.strikingwomen.org, created by the authors for schools and community groups and offering resources on migration, women’s and labour rights based on research on South Asian women in the UK

CMB lensing and primordial squeezed non-Gaussianity

Squeezed primordial non-Gaussianity can strongly constrain early-universe physics, but it can only be observed on the CMB after it has been gravitationally lensed. We give a new simple non-perturbative prescription for accurately calculating the effect of lensing on any squeezed primordial bispectrum shape, and test it with simulations. We give the generalization to polarization bispectra, and discuss the effect of lensing on the trispectrum. We explain why neglecting the lensing smoothing effect does not significantly bias estimators of local primordial non-Gaussianity, even though the change in shape can be >~10%. We also show how tau_NL trispectrum estimators can be well approximated by much simpler CMB temperature modulation estimators, and hence that there is potentially a ~10-30% bias due to very large-scale lensing modes, depending on the range of modulation scales included. Including dipole sky modulations can halve the tau_NL error bar if kinematic effects can be subtracted using known properties of the CMB temperature dipole. Lensing effects on the g_NL trispectrum are small compared to the error bar. In appendices we give the general result for lensing of any primordial bispectrum, and show how any full-sky squeezed bispectrum can be decomposed into orthogonal modes of distinct angular dependence.Comment: 22 pages, 6 figures; minor edits to match published versio

Barriers to, and facilitators of, the prevention of unintentional injury in children in the home: a systematic review and synthesis of qualitative research

Journal ArticleMeta-AnalysisResearch Support, Non-U.S. Gov'tReviewBACKGROUND: This review considers barriers to, and facilitators of, success for interventions to reduce unintentional injury to children in the home through supply and/or installation of home safety equipment, and looks at risk assessments. METHODS: A systematic review of qualitative research. Bibliographic databases were searched for studies on interventions to reduce unintentional child injury in the home, or on related attitudes and behaviours. Studies were quality appraised, findings extracted, and a conceptual framework was developed to assess factors affecting the success of interventions. RESULTS: Nine peer-reviewed journal articles were included. Barriers and facilitators were highlighted at organisational, environmental and personal levels. Effective provision of safety equipment involves ongoing support with installation and maintenance. Take up and success of interventions depends on adjusting interventions according to practical limitations and parents' cultural expectations. A particular barrier was parents' inability to modify rented or shared accommodation. CONCLUSIONS: The review highlights ways in which health inequalities affect the take up and success of home safety interventions, and how health workers can use this knowledge to facilitate future interventions.NICE Centre for Public Health Excellenc

Twenty questions about design behavior for sustainability, report of the International Expert Panel on behavioral science for design

How behavioral scientists, engineers, and architects can work together to advance how we all understand and practice design—in order to enhance sustainability in the built environment, and beyond.https://www.nature.com/documents/design_behavior_for_sustainability.pdfPublished versio