Monitoring of ice-shelf and sub-ice-shelf ocean temperatures represents an important component in understanding ice-sheet stability. Continuous monitoring is challenging due to difficult surface ...access, difficulties in penetrating the ice shelf, and the need for long-term operation of non-recoverable sensors. We aim to develop rapid lightweight drilling and near-continuous fiber-optic temperature-monitoring methods to meet these challenges. During November 2011, two instrumented moorings were installed within and below the McMurdo Ice Shelf (a sub-region of the Ross Ice Shelf, Antarctica) at Windless Bight. We used a combination of ice coring for the upper portion of each shelf borehole and hot-point drilling for penetration into the ocean. The boreholes provided temporary access to the ice-shelf cavity, into which distributed temperature sensing (DTS) fiber-optic cables and conventional pressure/temperature transducers were installed. The DTS moorings provided near-continuous (in time and depth) observations of ice and ocean temperatures to a depth of almost 800 m beneath the ice-shelf surface. Data received document the presence of near-freezing water throughout the cavity from November through January, followed by an influx of warmer water reaching ∼150 m beneath the ice-shelf base during February and March. The observations demonstrate prospects for achieving much higher spatial sampling of temperature than more conventional oceanographic moorings.
Structure in the Eridani Debris Disk Greaves, J. S; Holland, W. S; Wyatt, M. C ...
The Astrophysical journal,
02/2005, Letnik:
619, Številka:
2
Journal Article
Functional magnetic resonance imaging (fMRI) allows non-invasive assessment of human brain function in vivo by detecting blood flow differences. In this review, we want to illustrate the background ...and different aspects of performing functional magnetic resonance imaging (fMRI) in the pediatric age group. An overview over current and future applications of fMRI will be given, and typical problems, pitfalls, and benefits of doing fMRI in the pediatric age group are discussed. We conclude that fMRI can successfully be applied in children and holds great promise for both research and clinical purposes.
We describe a search for submillimeter emission in the vicinity of one of the most distant, luminous galaxies known, HerMES FLS3, at z = 6.34, exploiting it as a signpost to a potentially biased ...region of the early universe, as might be expected in hierarchical structure formation models. Imaging to the confusion limit with the innovative, wide-field submillimeter bolometer camera, SCUBA-2, we are sensitive to colder and/or less luminous galaxies in the surroundings of HFLS3. We use the Millennium Simulation to illustrate that HFLS3 may be expected to have companions if it is as massive as claimed, but find no significant evidence from the surface density of SCUBA-2 galaxies in its vicinity, or their colors, that HFLS3 marks an overdensity of dusty, star-forming galaxies. We cannot rule out the presence of dusty neighbors with confidence, but deeper 450 mu m imaging has the potential to more tightly constrain the redshifts of nearby galaxies, at least one of which likely lies at z > ~ 5. If associations with HFLS3 can be ruled out, this could be taken as evidence that HFLS3 is less biased than a simple extrapolation of the Millennium Simulation may imply. This could suggest either that it represents a rare short-lived, but highly luminous, phase in the evolution of an otherwise typical galaxy, or that this system has suffered amplification due to a foreground gravitational lens and so is not as intrinsically luminous as claimed.
The Vega debris disc: A view from Herschel Sibthorpe, B.; Vandenbussche, B.; Greaves, J. S. ...
Astronomy and astrophysics (Berlin),
07/2010, Letnik:
518, Številka:
1
Journal Article
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We present five band imaging of the Vega debris disc obtained using the Herschel Space Observatory. These data span a wavelength range of 70–500 μm with full-width half-maximum angular resolutions of ...5.6–36.9”. The disc is well resolved in all bands, with the ring structure visible at 70 and 160 μm. Radial profiles of the disc surface brightness are produced, and a disc radius of 11” (~85 AU) is determined. The disc is seen to have a smooth structure thoughout the entire wavelength range, suggesting that the disc is in a steady state, rather than being an ephemeral structure caused by the recent collision of two large planetesimals.
Structure in the ε Eridani Debris Disk Greaves, J. S.; Holland, W. S.; Wyatt, M. C. ...
Astrophysical journal/The Astrophysical journal,
02/2005, Letnik:
619, Številka:
2
Journal Article
Although psychological distress and cognitive dysfunction are well documented in adults with multiple sclerosis (MS), they are poorly understood in children with the disease. Psychosocial difficulty ...experienced by children and adolescents with MS involves factors common to all chronic illnesses in children, as well as MS-specific factors. The psychosocial manifestations of the disease may affect the patient's self-image, role functioning, mood, and cognition to adversely affect schooling, interpersonal relationships, and treatment compliance. Furthermore, the impact of having a family member with MS may affect overall family functioning. Assessment and interventions for psychosocial and cognitive problems in pediatric MS should be multidisciplinary in nature and address the child's functioning at home, school, and among peers, as well as the effect on the family.
Eight nearby stars with known giant planets have been searched for thermal emission in the submillimetre arising from dust debris. The null results imply quantities of dust typically less than 0.02 ...Earth masses per star. Conversely, literature data for 20 Sun-like stars with debris discs show that ≤ 5 per cent have gas giants inside a few astronomical units — but the dust distribution suggests that nearly all have more distant planets. The lack of overlap in these systems — i.e. few stars possess both inner planets and a disc — indicates that these phenomena either are not connected or are mutually exclusive. Comparison with an evolutionary model shows that debris masses are predicted to be low by the stellar ages of 2–8 Gyr (unless the colliding parent bodies are quite distant, located beyond 100–200 au), but it remains to be explained why stars that do have debris should preferentially only have distant planets. A simple idea is proposed that could produce these largely different systems, invoking a difference in the primordial disc mass. Large masses promote fast gas giant growth and inwards migration, whereas small masses imply slow evolution, low-mass gas giants and outwards migration that increases the collision rate of Kuiper Belt-like objects. This explanation neglects other sources of diversity between discs (such as density and planetesimal composition and orbits), but it does have the merit of matching the observational results.
A polarimeter has been built for use with the Submillimetre Common-User Bolometer Array (SCUBA), on the James Clerk Maxwell Telescope (JCMT) in Hawaii. SCUBA is the first of a new generation of ...highly sensitive submillimetre cameras, and the UK/Japan Polarimeter adds a polarimetric imaging/photometry capability in the wavelength range 350 to 2000 μm. Early science results range from measuring the synchrotron polarization of the black hole candidate Sgr A* to mapping magnetic fields inferred from polarized dust emission in Galactic star-forming clouds. We describe the instrument design, performance, observing techniques and data reduction processes, along with an assessment of the current and future scientific capability.
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