Internal Delensing of Cosmic Microwave Background Polarization B-Modes with the POLARBEAR Experiment.

Using only cosmic microwave background polarization data from the polarbear experiment, we measure B-mode polarization delensing on subdegree scales at more than 5σ significance. We achieve a 14% B-mode power variance reduction, the highest to date for internal delensing, and improve this result to 22% by applying for the first time an iterative maximum a posteriori delensing method. Our analysis demonstrates the capability of internal delensing as a means of improving constraints on inflationary models, paving the way for the optimal analysis of next-generation primordial B-mode experiments.

Exploring suicidal behaviours by probation clients-a qualitative near-lethal study.

Background: Existing research emphasizes that offenders serving community based sentences are at an increased risk of suicide compared with the general population, however, there is little understanding about the causes of this risk. The aim of the current research was to understand how to support probation clients and prevent suicide, by exploring the experiences of probation clients who carried out near-lethal suicide attempts whilst under probation supervision. Methods: In-depth interviews were carried out with seven probation clients who made near-lethal suicide attempts whilst serving a probation sentence. Data were analysed using Interpretative Phenomenological Analysis. Results: Participants recounted negative experiences which they perceived to be linked to their suicidal feelings and behaviours, such as experiencing bereavements, perceived loss of control over their mental state or situation, and difficulties relating to stages of their probation sentence. Participants expressed severe difficulties with trusting authorities, making disclosure of suicidal feelings problematic. However, participants emphasized the role that purposeful and meaningful activity can play in suicide prevention. Conclusions: Suicide prevention strategies must be tailored to the needs of probation clients across the UK. Mandatory training for probation staff is recommended to help reduce suicides, and support from external agencies should be sought where possible.

Joint analysis of BICEP2/keck array and Planck Data.

We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400 deg^{2} patch of sky centered on RA 0 h, Dec. -57.5°. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck has observed the full sky in polarization at seven frequencies from 30 to 353 GHz, but much less deeply in any given region (1.2 µK deg in Q and U at 143 GHz). We detect 150×353 cross-correlation in B modes at high significance. We fit the single- and cross-frequency power spectra at frequencies ≥150 GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r), using a prior on the frequency spectral behavior of polarized dust emission from previous Planck analysis of other regions of the sky. We find strong evidence for dust and no statistically significant evidence for tensor modes. We probe various model variations and extensions, including adding a synchrotron component in combination with lower frequency data, and find that these make little difference to the r constraint. Finally, we present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for r, and yields an upper limit r_{0.05}<0.12 at 95% confidence. Marginalizing over dust and r, lensing B modes are detected at 7.0σ significance.

Measurement of the cosmic microwave background polarization lensing power spectrum with the POLARBEAR experiment.

Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.

Evidence for gravitational lensing of the cosmic microwave background polarization from cross-correlation with the cosmic infrared background.

We reconstruct the gravitational lensing convergence signal from cosmic microwave background (CMB) polarization data taken by the Polarbear experiment and cross-correlate it with cosmic infrared background maps from the Herschel satellite. From the cross spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0σ and indication of the presence of a lensing B-mode signal at a significance of 2.3σ. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics.

Indirect comparisons of treatments based on systematic reviews of randomised controlled trials.

BACKGROUND: Randomised controlled trials are the most effective way to differentiate between the effects of competing interventions. However, head-to-head studies are unlikely to have been conducted for all competing interventions. AIM: Evaluation of different methodologies used to indirectly compare interventions based on meta analyses of randomised controlled trials. METHODS: Systematic review of Cochrane Database of Systematic Reviews, Cochrane Methodology Register, EMBASE and MEDLINE for reports including meta analyses that contained an indirect comparison. Searching was completed in July 2007. No restriction was placed on language or year of publication. RESULTS: Sixty-two papers identified contained indirect comparisons of treatments. Five different methodologies were employed: comparing point estimates (1/62); comparing 95% confidence intervals (26/62); performing statistical tests on summary estimates (8/62); indirect comparison using a single common comparator (20/62); and mixed treatment comparison (MTC) (7/62). The only methodologies that provide an estimate of the difference between the interventions under consideration and a measure of the uncertainty around that estimate are indirect comparison using a single common comparator and MTC. The MTC might have advantages over other approaches because it is not reliant on a single common comparator and can incorporate the results of direct and indirect comparisons into the analysis. Indirect comparisons require an underlying assumption of consistency of evidence. Utilising any of the methodologies when this assumption is not true can produce misleading results. CONCLUSIONS: Use of either indirect comparison using a common comparator or MTC provides estimates for use in decision making, with the preferred methodology being dependent on the available data.

Estimate of the cosmological bispectrum from the MAXIMA-1 cosmic microwave background map.

We use the measurement of the cosmic microwave background taken during the MAXIMA-1 flight to estimate the bispectrum of cosmological perturbations. We propose an estimator for the bispectrum that is appropriate in the flat sky approximation, apply it to the MAXIMA-1 data, and evaluate errors using bootstrap methods. We compare the estimated value with what would be expected if the sky signal were Gaussian and find that it is indeed consistent, with a chi(2) per degree of freedom of approximately unity. This measurement places constraints on models of inflation.

Tests for Gaussianity of the MAXIMA-1 cosmic microwave background map.

Gaussianity of the cosmological perturbations is one of the key predictions of standard inflation, but it is violated by other models of structure formation such as cosmic defects. We present the first test of the Gaussianity of the cosmic microwave background (CMB) on subdegree angular scales, where deviations from Gaussianity are most likely to occur. We apply the methods of moments, cumulants, the Kolmogorov test, the chi(2) test, and Minkowski functionals in eigen, real, Wiener-filtered, and signal-whitened spaces, to the MAXIMA-1 CMB anisotropy data. We find that the data, which probe angular scales between 10 arcmin and 5 deg, are consistent with Gaussianity. These results show consistency with the standard inflation and place constraints on the existence of cosmic defects.

Cosmology from MAXIMA-1, BOOMERANG, and COBE DMR cosmic microwave background observations.

Recent results from BOOMERANG-98 and MAXIMA-1, taken together with COBE DMR, provide consistent and high signal-to-noise measurements of the cosmic microwave background power spectrum at spherical harmonic multipole bands over 2

Measurement of a Peak in the Cosmic Microwave Background Power Spectrum from the North American Test Flight of Boomerang.

We describe a measurement of the angular power spectrum of anisotropies in the cosmic microwave background (CMB) at scales of 0&fdg;3 to 5 degrees from the North American test flight of the Boomerang experiment. Boomerang is a balloon-borne telescope with a bolometric receiver designed to map CMB anisotropies on a long-duration balloon flight. During a 6 hr test flight of a prototype system in 1997, we mapped more than 200 deg(2) at high Galactic latitudes in two bands centered at 90 and 150 GHz with a resolution of 26&arcmin; and 16&farcm;5 FWHM, respectively. Analysis of the maps gives a power spectrum with a peak at angular scales of 1 degrees with an amplitude 70 µK(CMB).

A Measurement of Omega from the North American Test Flight of Boomerang.

We use the angular power spectrum of the cosmic microwave background, measured during the North American test flight of the Boomerang experiment, to constrain the geometry of the universe. Within the class of cold dark matter models, we find that the overall fractional energy density of the universe Omega is constrained to be 0.85

A flat Universe from high-resolution maps of the cosmic microwave background radiation

The blackbody radiation left over from the Big Bang has been transformed by the expansion of the Universe into the nearly isotropic 2.73 K cosmic microwave background. Tiny inhomogeneities in the early Universe left their imprint on the microwave background in the form of small anisotropies in its temperature. These anisotropies contain information about basic cosmological parameters, particularly the total energy density and curvature of the Universe. Here we report the first images of resolved structure in the microwave background anisotropies over a significant part of the sky. Maps at four frequencies clearly distinguish the microwave background from foreground emission. We compute the angular power spectrum of the microwave background, and find a peak at Legendre multipole Ipeak = (197 +/- 6), with an amplitude delta T200 = (69 +/- 8) microK. This is consistent with that expected for cold dark matter models in a flat (euclidean) Universe, as favoured by standard inflationary models.

Acceptability of flexible sigmoidoscopy screening in older adults in the United Kingdom.

OBJECTIVES: To assess the acceptability of bowel cancer screening using flexible sigmoidoscopy (FS). SETTING: Adults aged 55 to 64 recruited from general practices in Welwyn Garden City and Leicester, which were the pilot and start up centres of a multicentred randomised controlled trial of FS screening (the ICRF/MRC Flexible Sigmoidoscopy Screening Trial). METHODS: Screenees (n=4422) were sent a three month follow up questionnaire that included measures of satisfaction with information given before the test, facilities at the test unit, attitudes of the staff, and explanation of the results. Measures of pain, embarrassment, feelings of being "in control" during the test, willingness to encourage others to have the test, and gladness to have participated were also included. In addition, semistructured telephone interviews were conducted with 60 screenees, stratified by screening outcome and gender. RESULTS: The follow up questionnaire was completed by 94% of screenees. Responses indicated a high level of satisfaction with the procedure: 99% were satisfied with the information given before the test, the facilities, the attitudes of the staff, and the explanation of their results; 91% reported only mild or no pain; 97% reported little or no embarrassment; and 99% were glad they had the test. Satisfaction ratings varied little by gender or outcome group. The quantitative results were reinforced by the qualitative data, which also revealed high acceptability. CONCLUSION: In the context of a clinical trial with dedicated trial staff, FS is a well tolerated procedure. There are high levels of satisfaction with service provision and positive attitudes towards the programme.

Detecting and preventing postnatal depression.

Usually only a quarter of postnatal depression cases are identified. Jo Borrill discusses the role of nurses in detecting depression in mothers and giving them support.

Fuels for memory: the role of oxygen and glucose in memory enhancement.

Recent studies indicate that some aspects of memory can be enhanced by the administration of oxygen or glucose. Considering the dependency of glucose metabolism upon oxygen supply, the present study predicted that administering a combination of 100% oxygen with glucose would have greater memory-enhancing effects than when either substance was administered alone. In a placebo-controlled study, 104 healthy adults were given a glucose or placebo drink, and inhaled 100% oxygen or air for 1 min, before carrying out a number of everyday memory tasks designed to measure short-term and long-term memory. Results showed support for the enhancing effects of oxygen (but not for glucose) on delayed recall. These findings are discussed in relation to the possible cholinergic properties of oxygen and glucose and the implications for their clinical use.

Chronic fatigue syndrome: a qualitative investigation of patients' beliefs about the illness.

The chronic fatigue syndrome is a disabling chronic condition of uncertain cause. Previous studies have found that patients seen in hospital clinics with the syndrome often strongly believe that their illness is physical in nature and minimize the role of psychological and social factors. There is also evidence that patients cope by avoiding activity. However, almost all of these studies have assessed illness beliefs only by questionnaire. The aim of this study was to explore the nature and origin of illness beliefs in more detail using in-depth interviews and a qualitative analysis of patient responses. Sixty-six consecutive referrals meeting Oxford criteria for chronic fatigue syndrome were recruited. Analysis of responses indicated that, whereas the most commonly described explanation for the illness was a physical one, more than half the patients also believed "stress" had played a role. Patients believed that they could partially control the symptoms by reducing activity but felt helpless to influence the physical disease process and hence the course of the illness. Patients reported that they had arrived at these beliefs about the illness after prolonged reflection on their own experience combined with the reading of media reports, self help books, and patient group literature. The views of health professionals played a relatively small role. There is potentially a considerable opportunity to help patients arrive at a wider and more enabling explanation of their illness when they first present to primary care.