The young star β Pictoris is well known for its dusty debris disk produced through collisional grinding of planetesimals, kilometre-sized bodies in orbit around the star. In addition to dust, small ...amounts of gas are also known to orbit the star; this gas is likely the result of vaporisation of violently colliding dust grains. The disk is seen edge on and from previous absorption spectroscopy we know that the gas is very rich in carbon relative to other elements. The oxygen content has been more difficult to assess, however, with early estimates finding very little oxygen in the gas at a C/O ratio that is 20 × higher than the cosmic value. A C/O ratio that high is difficult to explain and would have far-reaching consequences for planet formation. Here we report on observations by the far-infrared space telescope Herschel, using PACS, of emission lines from ionised carbon and neutral oxygen. The detected emission from C+ is consistent withthat previously reported observed by the HIFI instrument on Herschel, while the emission from O is hard to explain without assuming a higher density region in the disk, perhaps in the shape of a clump or a dense torus required to sufficiently excite the O atoms. A possible scenario is that the C/O gas is produced by the same process responsible for the CO clump recently observed by the Atacama Large Millimeter/submillimeter Array in the disk and that the redistribution of the gas takes longer than previously assumed. A more detailed estimate of the C/O ratio and the mass of O will have to await better constraints on the C/O gas spatial distribution.
Brachioplasty is aesthetic reshaping of the upper arm after removal of excess medial skin and fat. Massive weight loss patients evolve a severe arm deformity that extends through the axilla and onto ...the chest. Prevalent operations are incomplete and leave conspicuous scars along the bicipital groove that end as Ts or Zs in the axilla. The L brachioplasty starts with a long ellipse centered over the lower half of the inner arm that sweeps up to the deltopectoral groove. A shorter ellipse is connected at right angles through the axilla onto the chest. The V flap formed between the ellipses is advanced across the axilla to raise the posterior axillary fold. An improved arm, axilla, and chest have an L-shaped zigzag crossing the axilla.
L brachioplasty, along with upper body lifting, was applied to 24 female weight loss patients over the last 2 years. Ultrasound-assisted lipoplasty was also performed in five patients. All patients were interviewed. Follow-up ranged from 6 to 28 months.
All 22 patients were improved and pleased. One patient requested and received a limited scar revision. Three patients had delayed healing at the tip of the triangular flap. Four seromas near the elbow responded to multiple aspirations. One hypertrophic scar was improved with intense pulsed light.
The L-shaped brachioplasty is an innovative, effective, reliable, aesthetic, and safe technique. Integrating the brachioplasty into the upper body lift improves the contours of the axilla, breast, and upper lateral chest, contributing to improved harmonious body contour.
SCUBA-2: A large-format TES array for submillimetre astronomy Audley, M.D; Holland, W.S; Duncan, W.D ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
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520, Številka:
1-3
Journal Article
Recenzirano
SCUBA-2, which replaces the Submillimetre Common User Bolometer Array (SCUBA) (Mon. Not. R. Astron. Soc. 303 (1999) 659) on the James Clerk Maxwell telescope in 2006, will be the first CCD-like array ...for submillimeter astronomy. Unlike previous detectors which have used discrete bolometers, SCUBA-2 has two DC-coupled, monolithic, filled arrays with a total of ∼10,000 bolometers. It will offer simultaneous imaging of an 8×8 arcmin field of view at wavelengths of 850 and 450μm. SCUBA-2 is expected to have a huge impact on the study of galaxy formation and evolution in the early Universe as well as star and planet formation in our own Galaxy. Mapping the sky to the same S/N up to 1000 times faster than SCUBA, it will also act as a pathfinder for the new submillimetre interferometers such as ALMA. SCUBA-2's absorber-coupled pixels use superconducting transition edge sensors (Ph.D. Thesis, Stanford, 1995) operating at ∼120mK for photon noise limited performance. The monolithic silicon detector arrays are deep-etched by the Bosch process to isolate the pixels on silicon nitride membranes (Nucl. Instr. and Meth. A, these proceedings). Electrical connections are made through indium bump bonds to a backplane that incorporates a SQUID time-domain multiplexer. We describe the key technologies that make SCUBA-2 possible and give an update on the considerable progress in the detector development and instrument design that has taken place over the last 2 years.
Far-infrared Herschel images of the epsilon Eridani system, seen at a fifth of the Sun's present age, resolve two belts of debris emission. Fits to the 160 mu m PACS image yield radial spans for ...these belts of 12-16 and 54-68 AU. The south end of the outer belt is thickapproximate10% brighter than the north end in the PACS+SPIRE images at 160, 250, and 350 mu m, indicating a pericenter glow attributable to a planet "c." From this asymmetry and an upper bound on the offset of the belt center, this second planet should be mildly eccentric (e sub(c) thickapproximate 0.03-0.3). Compared to the asteroid and Kuiper Belts of the young Sun, the epsilon Eri belts are intermediate in brightness and more similar to each other, with up to 20 km sized collisional fragments in the inner belt totaling thickapproximate5% of an Earth mass. This reservoir may feed the hot dust close to the star and could send many impactors through the Habitable Zone, especially if it is being perturbed by the suspected planet epsilon Eri b, at semi-major axis thickapproximate3 AU.
Ambipolar diffusion (ion-neutral drift) is believed to be one of the key processes in star formation, regulating the rate of collapse of cloud cores. A by-product of the diffusion process is ...collisional alignment of dust grains in molecular clouds, and this can be tested observationally. We have searched for velocity differences between neutral and ionic molecular lines in three star-forming cloud cores (W3, S106 and NGC 7538), and found increases in the ion-neutral drift speed with higher degrees of submillimetre polarization (and hence grain alignment efficiency). However, the velocity differences are only ∼ 0.5 km s−1 even in the most polarized cores (p ≈ 3 per cent), a result which favours grain axial ratios a/b ∼ 0.25, while the maximum observed polarizations require larger a/b values, approximately ≥ 0.7. The number of sources observed is small, but the results suggest that ion-neutral drift does occur in magnetized star-forming cores, although grains may be aligned at surprisingly low drift speeds.
The prevalence of cerebrovascular disease in children is much higher than most clinicians and neuroradiologists suspect, when all primary and secondary causes are considered. Most signal alterations ...found on MR imaging in childhood central nervous system pathologic conditions result from causes other than a decrease in tissue perfusion. In addition to conventional MR imaging, the ability to assess changes in tissue water by diffusion imaging and tissue perfusion by perfusion-weighted imaging can prove useful to asses cerebral hemodynamics in various pathologic disorders. Exogenous contrast bolus dynamic perfusion-weighted imaging is especially useful in children to differentiate between ischemic injury and other conditions that may alter T2 relaxation, such as demyelination and edema. Perfusion imaging has proved to be a robust and valuable tool to assess the hemodynamic component in childhood CNS disease related to neoplasms and complications from their therapy, cerebrovascular occlusive disease, childhood CNS arteriopathies and trauma.
The crystal structure of a lysine 49 variant phospholipase A2 (K49 PLA2) has been determined at 2.0-A resolution. This particular phospholipase A2, purified from the venom of the eastern cottonmouth ...(Agkistrodon piscivorus piscivorus), a North American pit viper, differs significantly from others studied crystallographically because of replacement of the aspartate residue at position 49, whose side chain is important in calcium binding, by lysine. The crystallographic analysis of K49 PLA2 was undertaken to assess the structural ramifications of this substitution, particularly as they affect the binding mechanism of both the calcium cofactor and the phospholipid substrate. The protein crystals are tetragonal, space group P4(1)2(1)2, with unit cell dimensions of a = b = 71.7 (1) and c = 57.8 (3) A. Preliminary phases were obtained by molecular replacement techniques with a search model derived from the refined 2.5-A structure of a rattle-snake venom phospholipase A2 (Brunie, S., Bolin, J., Gewirth, D., and Sigler, P. B. (1985) J. Biol. Chem. 260, 9742-9749). The starting model gave an initial crystallographic RF of 0.526 (RF = sigma parallel to Fo /-/ Fc parallel to /sigma/Fo/). The structure was refined against all data to 2.0-A resolution. The final RF is 0.158. The final model includes 150 discrete water molecules. The K49 PLA2 model is composed primarily of alpha-helices joined by loops, some of which are quite extensive. Although dissimilarities are observed in the loop regions, the helical portions are very similar to those in other known phospholipase A2 structures. The proposed catalytic center (His48, Tyr73, and Asp99) is also structurally conserved. The region in K49 PLA2 corresponding to the calcium-binding site in other phospholipases A2 is occupied by the epsilon-amino group of lysine 49.
Military planners use “Operational Design” (OD) methods to develop an understanding of systems and relationships in complex operational environments. Here, we present Causeworks, a visual analytics ...application for OD teams to collaboratively build causal models of environments and use analytics to understand and find solutions to affect them. Collaborative causal modelling can help teams craft better plans, but there are unique challenges in developing synchronous collaboration tools for building and using causal models. Collaboration systems typically organize information around varying degrees of synchronization between data “values” and user “views.” Our contribution is in extending this collaboration framework to include analytics as layers that are by nature derived from the data values but utilized and displayed temporarily as private views. We describe how Causeworks overlays analytics inputs and outputs over a shared causal model to flexibly support multiple modeling tasks simultaneously in a collaborative environment with minimal state management burden on users.
This paper describes a James Clerk Maxwell Telescope (JCMT) legacy survey that has been awarded roughly 500 hr of observing time to be carried out from 2007 to 2009. In this survey, we will map with ...SCUBA‐2 (Submillimetre Common‐User Bolometer Array 2) almost all of the well‐known low‐mass and intermediate‐mass star‐forming regions within 0.5 kpc that are accessible from the JCMT. Most of these locations are associated with the Gould Belt. From these observations, we will produce a flux‐limited snapshot of star formation near the Sun, providing a legacy of images, as well as point‐source and extended‐source catalogs, over almost 700 deg2of sky. The resulting images will yield the first catalog of prestellar and protostellar sources selected by submillimeter continuum emission, and should increase the number of known sources by more than an order of magnitude. We will also obtain with the array receiver HARP (Heterodyne Array Receiver Program) CO maps, in three CO isotopologues, of a large typical sample of prestellar and protostellar sources. We will then map the brightest hundred sources with the SCUBA‐2 polarimeter (POL‐2), producing the first statistically significant set of polarization maps in the submillimeter. The images and source catalogs will be a powerful reference set for astronomers, providing a detailed legacy archive for future telescopes, includingALMA,Herschel, andJWST.
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