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Polarization observations of the cosmic microwave background with the Cosmic Background Imager from September 2002 to May 2004 provide a significant detection of the f-mode polarization and reveal an angular power spectrum of polarized emission showing peaks and valleys that are shifted in phase by half a cycle relative to those of the total intensity spectrum. This key agreement between the phase of the observed polarization spectrum and that predicted on the basis of the total intensity spectrum provides support for the standard model of cosmology, in which dark matter and dark energy are the dominant constituents, the geometry is close to flat, and primordial density fluctuations are predominantly adiabatic with a matter power spectrum commensurate with inflationary cosmological models.

Design and performance details are given for the Cosmic Background Imager (CBI), an interferometer array that is measuring the power spectrum of fluctuations in the cosmic microwave background radiation (CMBR) for multipoles in the range \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $400< l< 3500$ \\end{document} . The CBI is located at an altitude of 5000 m in the Atacama Desert in northern Chile. It is a planar synthesis array with 13 0.9 m diameter antennas on a 6 m diameter tracking platform. Each antenna has a cooled, low‐noise receiver operating in the 26–36 GHz band. Signals are cross‐correlated in an analog filterbank correlator with 10 1 GHz bands. This allows spectral index measurements that can be used to distinguish CMBR signals from diffuse galactic foregrounds. A 1.2 kHz 180° phase‐switching scheme is used to reject cross talk and low‐frequency pick‐up in the signal processing system. The CBI has a three‐axis mount that allows the tracking platform to be rotated about the optical axis, providing improved (u, \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $v$ \\end{document} ) coverage and a powerful discriminant against false signals generated in the receiving electronics. Rotating the tracking platform also permits polarization measurements when some of the antennas are configured for the orthogonal polarization.

We report upper limits on the polarization of the CMBR as measured with the Cosmic Background Imager, a 13 element interferometer that operates in the 26-36 GHz band and is sited on Llano de Chajnantor in northern Chile. The array consists of 90-cm Cassegrain antennas mounted on a steerable platform that can be rotated about the optical axis to facilitate polarization observations. The CBI employs single-mode circularly polarized receivers and it samples multipoles from l~400 to l~3500. The polarization data were calibrated on 3C279 and Tau A. The polarization observations consist of 278 hours of data on two fields taken in 2000, during the first CBI observing season. A joint likelihood analysis of the two fields yields three upper limits (95% c.l.) for \\mathcal{C}_l^{EE} = C^{EE}l(l+1)/(2pi) under the assumption that \\mathcal{C}_l^{BB}=0: 49.0 microK^2 (l=603); 164 microK^2 (l=1144); and 630 microK^2 (l=2048).

Three exploratory studies in the field of the services for maladjusted, children are described, in this volume.The first study is based on data obtained from child guidance clinics in those boroughs constituting the Outer London area. Initially the data is presented as rates of referral of children to the- thirty clinics concerned. An examination of these figures is then carried out in terms of the age and sex of the children and the source of referral. Further refinements of this and other data collected about these areas enables the second stage of this study to progress. A causal analysis is carried out which seeks to explain why it is that the rates of referral to child guidance clinics and maladjusted schools vary from one area to another. The concept of social ethos is used as an independent variable and the number of clinic staff available as an intervening variable. The second study addresses itself to the problem of why it is that some families who are referred to child guidance clinics co-operate with the clinics while others do not. An explanatory model based upon both sociological and psychological approaches is developed. This is tested using the techniques of causal analysis. Finally the causal links are examined in the light of the clients expectations of the clinic and a role conflict model is used to illustrate the causal structure.