Mounted on the sides of two widely separated spacecraft, the two Heliospheric Imager (HI) instruments onboard NASA’s STEREO mission view, for the first time, the space between the Sun and Earth. ...These instruments are wide-angle visible-light imagers that incorporate sufficient baffling to eliminate scattered light to the extent that the passage of solar coronal mass ejections (CMEs) through the heliosphere can be detected. Each HI instrument comprises two cameras, HI-1 and HI-2, which have 20° and 70° fields of view and are off-pointed from the Sun direction by 14.0° and 53.7°, respectively, with their optical axes aligned in the ecliptic plane. This arrangement provides coverage over solar elongation angles from 4.0° to 88.7° at the viewpoints of the two spacecraft, thereby allowing the observation of Earth-directed CMEs along the Sun – Earth line to the vicinity of the Earth and beyond. Given the two separated platforms, this also presents the first opportunity to view the structure and evolution of CMEs in three dimensions. The STEREO spacecraft were launched from Cape Canaveral Air Force Base in late October 2006, and the HI instruments have been performing scientific observations since early 2007. The design, development, manufacture, and calibration of these unique instruments are reviewed in this paper. Mission operations, including the initial commissioning phase and the science operations phase, are described. Data processing and analysis procedures are briefly discussed, and ground-test results and in-orbit observations are used to demonstrate that the performance of the instruments meets the original scientific requirements.
The
Sun Watcher with Active Pixels and Image Processing
(SWAP) is an EUV solar telescope onboard ESA’s
Project for Onboard Autonomy 2
(PROBA2) mission launched on 2 November 2009. SWAP has a spectral ...bandpass centered on 17.4 nm and provides images of the low solar corona over a 54×54 arcmin field-of-view with 3.2 arcsec pixels and an imaging cadence of about two minutes. SWAP is designed to monitor all space-weather-relevant events and features in the low solar corona. Given the limited resources of the PROBA2 microsatellite, the SWAP telescope is designed with various innovative technologies, including an off-axis optical design and a CMOS–APS detector. This article provides reference documentation for users of the SWAP image data.
The presence and severity of the chronic pain syndrome fibromyalgia (FM) is associated with unresolved stress and emotional regulation difficulties. Written emotional disclosure is intended to reduce ...stress and may improve health of people with FM.
This study tests the effects of at-home, written emotional disclosure about stressful experiences on the health of people with FM and uses multiple follow-ups to track the time course of effects of disclosure.
Adults with FM (intention-to-treat, n=83; completers, n=72) were randomized to write for 4 days at home about either stressful experiences (disclosure group) or neutral time management (control group). Group differences in immediate mood effects and changes in health from baseline to 1-month and 3-month follow-ups were examined.
Written disclosure led to an immediate increase in negative mood, which did not attenuate across the 4 writing days. Repeated-measures analyses from baseline to each follow-up point were conducted on both intention-to-treat and completer samples, which showed similar outcomes. At 1 month, disclosure led to few health benefits, but control writing led to less negative affect and more perceived support than did disclosure. At 3-month follow-up, these negative affect and social support effects disappeared, and written disclosure led to a greater reduction in global impact, poor sleep, health care utilization, and (marginally) physical disability than did control writing. Interpretation of these apparent benefits needs to be made cautiously, however, because the disclosure group had somewhat poorer health than controls at baseline and the control group showed some minor worsening over time.
Written emotional disclosure can be conducted at home, and there is tentative evidence that disclosure benefits the health of people with FM. The benefits, however, may be delayed for several months after writing and may be of limited clinical significance.
Methanogenesis and methane oxidation are the major biological processes affecting the global cycling of the powerful greenhouse gas methane. To carry out the two alternative bioconversions, Nature ...has cleverly recycled key reactions for the C1 transfers between the oxidation levels of formaldehyde and formate, and these involve analogous enzyme systems and common specialized cofactors, methanopterin and methanofuran. Until recently, the distribution of these functions has been limited to methanogenic archaea and methylotrophic proteobacteria, and their evolutionary history remained obscure. Single interdomain lateral transfer of the respective genes has been suggested to play a role. Here we show that genes for C1 transfer reactions linked to methanopterin and methanofuran are also present in diverse representatives of the enigmatic bacterial clade, the Planctomycetes. Phylogenetic analysis places the planctomycete sequences as distantly from their archaeal counterparts as from their proteobacterial counterparts, suggesting novel scenarios for the evolution of the C1 transfer functions in both methanogens and methylotrophs. This finding suggests a possible role for Planctomycetes in the evolution of the methane cycle on Earth.
SWAP (Sun Watcher using Active Pixel system detector and image processing) is a solar imager in the extreme ultraviolet (EUV) that has been selected to fly in 2007 on the PROBA 2 technological ...platform, an ESA program. SWAP will use an off-axis Ritchey Chrétien telescope equipped with an EUV enhanced active pixel sensor detector (coated APS). This type of detector has advantages that promise to be very profitable for solar EUV imaging. SWAP will provide solar coronal images at a 1-min cadence in a bandpass centered on 17.5
nm. Observations with this specific wavelength allow detecting phenomena, such as solar flares or EIT-waves, associated with the early phase of coronal mass ejections. Image processing software will be developed that automatically detects these phenomena and sends out space weather warnings. Together with its sister instrument LYRA, also onboard PROBA 2, SWAP will serve as a high performance solar monitoring tool to be used in operational space weather forecasting. The SWAP data will complement the solar observations provided by instruments like SOHO-EIT, and STEREO-SECCHI.
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