Superconducting Films for Absorber-Coupled MKID Detectors for Sub-Millimeter and Far-Infrared Astronomy

We describe measurements of the properties, at dc, gigahertz, and terahertz frequencies, of thin (10 nm) aluminum films with 10 ohm/{rm square}$ normal state sheet resistance. Such films can be applied to construct microwave kinetic inductance detector arrays for submillimeter and far-infrared astronomical applications in which incident power excites quasiparticles directly in a superconducting resonator that is configured to present a matched-impedance to the high frequency radiation being detected. For films 10 nm thick, we report normal state sheet resistance, resistance-temperature curves for the superconducting transition, quality factor and kinetic inductance fraction for microwave resonators made from patterned films, and terahertz measurements of sheet impedance measured with a Fourier Transform Spectrometer. We compare properties with similar resonators made from niobium 600 nm thick

Stretch for the treatment and prevention of contractures (Review)

Background Contractures are a common complication of neurological and non-neurological conditions, and are characterised by a reduction in joint mobility. Stretch is widely used for the treatment and prevention of contractures. However, it is not clear whether stretch is effective. This review is an update of the original 2010 version of this review. Objectives The aim of this review was to determine the effects of stretch on contractures in people with, or at risk of developing, contractures.The outcomes of interest were joint mobility, quality of life, pain, activity limitations, participation restrictions, spasticity and adverse events. Search methods In November 2015 we searched CENTRAL, DARE, HTA; MEDLINE; Embase; CINAHL; SCI-EXPANDED; PEDro and trials registries. Selection criteria We included randomised controlled trials and controlled clinical trials of stretch applied for the purpose of treating or preventing contractures. Data collection and analysis Two review authors independently selected trials, extracted data, and assessed risk of bias. The outcomes of interest were joint mobility, quality of life, pain, activity limitations, participation restrictions and adverse events. We evaluated outcomes in the short term (up to one week after the last stretch) and in the long term (more than one week). We expressed effects as mean differences (MD) or standardised mean differences (SMD) with 95% confidence intervals (CI). We conducted meta-analyses with a random-effects model. We assessed the quality of the body of evidence for the main outcomes using GRADE.Main results Forty-nine studies with 2135 participants met the inclusion criteria. No study performed stretch for more than seven months. Just over half the studies (51%) were at low risk of selection bias; all studies were at risk of detection bias for self reported outcomes such as pain and at risk of performance bias due to difficulty of blinding the intervention. However, most studies were at low risk of detection bias for objective outcomes including range of motion, and the majority of studies were free from attrition and selective reporting biases. The effect of these biases were unlikely to be important, given that there was little benefit with treatment. There was high-quality evidence that stretch did not have clinically important short-term effects on joint mobility in people with neurological conditions (MD 2°; 95% CI 0° to 3°; 26 studies with 699 participants) or non-neurological conditions (SMD 0.2, 95% CI 0 to 0.3, 19 studies with 925 participants). In people with neurological conditions, it was uncertain whether stretch had clinically important short-term effects on pain (SMD 0.2; 95% CI -0.1 to 0.5; 5 studies with 174 participants) or activity limitations (SMD 0.2; 95% CI -0.1 to 0.5; 8 studies with 247 participants). No trials examined the short-term effects of stretch on quality of life or participation restrictions in people with neurological conditions. Five studies involving 145 participants reported eight adverse events including skin breakdown, bruising, blisters and pain but it was not possible to statistically analyse these data. In people with non-neurological conditions, there was high-quality evidence that stretch did not have clinically important short-term effects on pain (SMD-0.2, 95%CI -0.4 to 0.1; 7 studies with 422 participants) and moderate-quality evidence that stretch did not have clinically important short-term effects on quality of life (SMD 0.3, 95% CI -0.1 to 0.7; 2 studies with 97 participants). The short-term effect of stretch on activity limitations (SMD 0.1; 95% CI -0.2 to 0.3; 5 studies with 356 participants) and participation restrictions were uncertain (SMD -0.2; 95% CI -0.6 to 0.1; 2 studies with 192 participants). Nine studies involving 635 participants reported 41 adverse events including numbness, pain, Raynauds’ phenomenon, venous thrombosis, need for manipulation under anaesthesia, wound infections, haematoma, flexion deficits and swelling but it was not possible to statistically analyse these data. Authors’ conclusions There was high-quality evidence that stretch did not have clinically important effects on joint mobility in people with or without neurological conditions if performed for less than seven months. Sensitivity analyses indicate results were robust in studies at risk of selection and detection biases in comparison to studies at low risk of bias. Sub-group analyses also suggest the effect of stretch is consistent in people with different types of neurological or non-neurological conditions. The effects of stretch performed for periods longer than sevenmonths have not been investigated. There was moderate- and high-quality evidence that stretch did not have clinically important short-term effects on quality of life or pain in people with non-neurological conditions, respectively. The short-term effects of stretch on quality of life and pain in people with neurological conditions, and the short-term effects of stretch on activity limitations and participation restrictions for people with and without neurological conditions are uncertain

A Quasioptical Vector Interferometer for Polarization Control

We present a mathematical description of a Quasioptical Vector Interferometer (QVI), a device that maps an input polarization state to an output polarization state by introducing a phase delay between two linear orthogonal components of the input polarization. The advantages of such a device over a spinning wave-plate modulator for measuring astronomical polarization in the far-infrared through millimeter are: 1. The use of small, linear motions eliminates the need for cryogenic rotational bearings, 2. The phase flexibility allows measurement of Stokes V as well as Q and U, and 3. The QVI allows for both multi-wavelength and broadband modulation. We suggest two implementations of this device as an astronomical polarization modulator. The first involves two such modulators placed in series. By adjusting the two phase delays, it is possible to use such a modulator to measure Stokes Q, U, and V for passbands that are not too large. Conversely, a single QVI may be used to measure Q and V independent of frequency. In this implementation, Stokes U must be measured by rotating the instrument. We conclude this paper by presenting initial laboratory results

Improving the Visible and Infrared Contrast Ratio of Microshutter Arrays

Three device improvements have been developed that dramatically enhance the contrast ratio of microshutters. The goal of a microshutter is to allow as much light through as possible when the shutters are in the open configuration, and preventing any light from passing through when they are in the closed position. The ratio of the transmitted light that is blocked is defined here as the contrast ratio. Three major components contribute to the improved performance of these microshutters: 1. The precise implementation of light shields, which protect the gap around the shutters so no light can leak through. It has been ascertained that without the light shield there would be a gap on the order of 1 percent of the shutter area, limiting the contrast to a maximum of 100. 2. The precise coating of the interior wall of each microshutter was improved with an insulator and metal using an angle deposition technique. The coating prevents any infrared light that finds an entrance on the surface of the microshutter cell from being emitted from a sidewall. Since silicon is in effect transparent to any light with a wavelength longer than .1 micrometer, these coatings are essential to blocking any stray signals when the shutters are closed. 3. A thin film of molybdenum nitride (MoN) was integrated onto the surface of the microshutter blade. This film provides the majority of light blockage over the microshutter and also ensures that the shutter can be operated over a wide temperature range by maintaining its flatness. These improvements were motivated by the requirements dictated by the James Webb Space Telescope NIRSpec instrument. The science goals of the NIRSpec require observing some of the very faintest objects in a given field of view that also may contain some very bright objects. To observe the faint objects, the light from the bright objects - which could be thousands of times brighter - must be completely blocked. If a closed microshutter is even slightly transmissive, a very bright object will still transmit a small signal, which can be larger than a signal from a very faint object transmitted through an open shutter. Since this situation can completely corrupt the results, it was necessary that the closed shutters be able to attenuate light by at least a factor of 2,000. There currently exist four flight-quality microshutter arrays that have been fully or are currently undergoing testing and the results support that the three improvements described above have successfully led to contrast levels greater than 50,000 in over 99 percent of the microshutters at an operating temperature of 35 K. Applications for these high-contrast microshutters are in the photomask generation and stepper equipment used to make integrated circuits and microelectromechanical (MEMS) devices. Since microshutters are a reconfigurable optical element, their versatility in these industries provides an improvement over printed masks and fixed projection alignment systems

Optical Design for the Submillimeter and Far InfraRed Experiment (SAFIRE)

The SAFIRE, the Submillimeter and Far InfraRed Experiment, was designed for interstellar physics in the airborne Observatory SOFIA. SAFIRE is a cryogenic Echelle Grating spectrograph for covering 27 to 470 microns; with R ranging from 2-6,000. Here we will discuss the details of the optical design, the design process, and the performance of the instrumen

Mission Concept for the Single Aperture Far-Infrared (SAFIR) Observatory

The Single Aperture Far-InfraRed (SAFIR) Observatory's science goals are driven by the fact that the earliest stages of almost all phenomena in the universe are shrouded in absorption by and emission from cool dust and gas that emits strongly in the far-infrared and submillimeter. Over the past several years, there has been an increasing recognition of the critical importance of this spectral region to addressing fundamental astrophysical problems, ranging from cosmological questions to understanding how our own Solar System came into being. The development of large, far-infrared telescopes in space has become more feasible with the combination of developments for the James Webb Space Telescope and of enabling breakthroughs in detector technology. We have developed a preliminary but comprehensive mission concept for SAFIR, as a 10 m-class far-infrared and submillimeter observatory that would begin development later in this decade to meet the needs outlined above. Its operating temperature (<4K) and instrument complement would be optimized to reach the natural sky confusion limit in the far-infrared with diffraction-limited peformance down to at least 40 microns. This would provide a point source sensitivity improvement of several orders of magnitude over that of Spitzer or Herschel, with finer angular resolution, enabling imaging and spectroscopic studies of individual galaxies in the early universe. We have considered many aspects of the SAFIR mission, including the telescope technology, detector needs and technologies, cooling method and required technology developments, attitude and pointing, power systems, launch vehicle, and mission operations. The most challenging requirements for this mission are operating temperature and aperture size of the telescope, and the development of detector arrays.Comment: 36 page

Doing it for the kids?: The discursive construction of the teenager and teenage sexuality in E4’s Skins

The teen series is often regarded by television scholars as an inherently American genre. Indeed, the genre is marked by US constructs, such as the cheerleader, jock, homecoming dance and prom and, in turn, teen television scholarship has focused almost exclusively on US texts. However, more recent years have seen the emergence of British teen drama series, most notably Skins (E4, 2007-), which has been so successful that it has spawned an (albeit short-lived) US version which aired on MTV. In an attempt to redress the dearth of academic study of British teen dramas, this article explores Skins in more detail. Journalistic discourse on the programme has frequently emphasised the series' nihilism in contrast to the didacticism that characterises its US generic counterparts, which the series' creators justify by claims for its authenticity. This article moves beyond the authentic/inauthentic debate to explore instead the discursive construction of the teenager and teenage sexuality in the specific context of broadcasting in the UK. Thus, after situating Skins in relation to the history of youth programming in Britain and, specifically, on Channel 4, the article will explore issue-led storylines involving teenage sexuality in more detail. It will argue that despite the programme's nihilistic ethos, Skins is underpinned by more conservative ideologies, particularly regarding the depiction of gender and sexuality. In turn, this ambivalence makes it difficult to discern the programme's ideological stance on sexual issues