7,518 research outputs found

    Weak lensing of the CMB

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    The cosmic microwave background (CMB) represents a unique source for the study of gravitational lensing. It is extended across the entire sky, partially polarized, located at the extreme distance of z=1100, and is thought to have the simple, underlying statistics of a Gaussian random field. Here we review the weak lensing of the CMB, highlighting the aspects which differentiate it from the weak lensing of other sources, such as galaxies. We discuss the statistics of the lensing deflection field which remaps the CMB, and the corresponding effect on the power spectra. We then focus on methods for reconstructing the lensing deflections, describing efficient quadratic maximum-likelihood estimators and delensing. We end by reviewing recent detections and observational prospects.Comment: 21 pages, 5 figures. Invited review for GRG special issue on gravitational lensin

    Features of central sensitisation in patients with shoulder pain : A feasibility study

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    Design. A case-control feasibility study, comparing people with unilateral shoulder pain and pain free controls. Background. Previous studies have suggested that central sensitisation (CS) may be present in people with shoulder pain, mostly based on testing of nociception rather than mechanosensitivity, both of which can change as part of CS. Changes in mechanosensitivity are important for physiotherapy, which often involves non-noxious mechanoreceptor stimulation. Objectives. This study tested sensitivity to arangea range of mechanical stimuli potentially associated with CS in people with and without shoulder pain, compared to asymptomatic individuals. It was hypothesised that if CS was present, the response to mechanoreceptor stimulation would be increased. Methods. Both shoulders in both groups were tested for sensitivity of static and dynamic touch, vibration and punctate stimulation, plus temporal summation and pressure pain threshold (PPT). Participants completed a demographic questionnaire, pain scales, PainDETECT for neuropathic pain, and QuickDASH for upper limb function. Results. PPT was found to be significantly lower in the affected compared to the unaffected shoulders (p<0.003), but no other statistically significant between-group differences were found. Conclusion. This study found a lowered PPT in people with unilateral shoulder pain compared with asymptomatic individuals, but no evidence of a heightened response to other forms of mechanoreceptor stimulation. The study protocol was suitable for future studies and the required participant numbers were established. The variation in findings between studies suggests that a larger longitudinal study may be warranted .Peer reviewedFinal Published versio

    Efficient Computation of CMB anisotropies in closed FRW models

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    We implement the efficient line of sight method to calculate the anisotropy and polarization of the cosmic microwave background for scalar and tensor modes in almost-Friedmann-Robertson-Walker models with positive spatial curvature. We present new results for the polarization power spectra in such models.Comment: 4 pages, 1 figure. Corrected/updated references. Accepted by ApJ. For the F90 source code see http://www.mrao.cam.ac.uk/~aml1005/cmb

    KCNE1 and KCNE2 provide a checkpoint governing voltage-gated potassium channel α-subunit composition

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    AbstractVoltage-gated potassium (Kv) currents generated by N-type α-subunit homotetramers inactivate rapidly because an N-terminal ball domain blocks the channel pore after activation. Hence, the inactivation rate of heterotetrameric channels comprising both N-type and non-N-type (delayed rectifier) α-subunits depends upon the number of N-type α-subunits in the complex. As Kv channel inactivation and inactivation recovery rates regulate cellular excitability, the composition and expression of these heterotetrameric complexes are expected to be tightly regulated. In a companion article, we showed that the single transmembrane segment ancillary (β) subunits KCNE1 and KCNE2 suppress currents generated by homomeric Kv1.4, Kv3.3, and Kv3.4 channels, by trapping them early in the secretory pathway. Here, we show that this trapping is prevented by coassembly of the N-type α-subunits with intra-subfamily delayed rectifier α-subunits. Extra-subfamily delayed rectifier α-subunits, regardless of their capacity to interact with KCNE1 and KCNE2, cannot rescue Kv1.4 or Kv3.4 surface expression unless engineered to interact with them using N-terminal A and B domain swapping. The KCNE1/2-enforced checkpoint ensures N-type α-subunits only reach the cell surface as part of intra-subfamily mixed-α complexes, thereby governing channel composition, inactivation rate, and—by extension—cellular excitability

    Privacy and Civilization, An Essay

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    The Right to Scrutinize Government: Toward a First Amendment Theory of Accountability

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    The speaker eschews the view that the press enjoys a preferred position under the first amendment and aligns his beliefs with the view of Alexander Meiklejohn-an informed public is necessary for the success of a self-governing democracy. Mr. Lewis analyzes case law and concludes that the Court should cautiously develop the principle of public accountability as a fundamental premise of the first amendment, guaranteeing a limited right of acquiring information to scrutinize government

    The Sullivan Decision

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    Keynote Address, Head Their Rising Voices: New York Times v. Sullivan-40 Years Later, The University of Tennessee College of Law, February 27, 2004. ** Mr. Lewis is a Pulitzer Prize

    The Press: Its Sins and Grace

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    Under the First Amendment, as it has come to be understood, the American press has more freedom than the press of any other country. I want to explore the question of what our press does with that great freedom. Does it show a matching responsibility? How well does it perform the role that the framers of the Constitution thought justified the protection they were giving us, the role of holding government accountable to the people? James Madison put it that in the United States the people, not the government, possess the absolute sovereignty. That was altogether different from Britain, he said, and it followed that the press must have a different degree of freedom in order to inform the people what the government was doing. And so, Madison concluded, the American press must be free when canvassing the merits and measures of public me

    Lawyers and Civilization

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    Give Me Liberty: Individual Rights In A Time Of War

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