4,908 research outputs found
Ion energy measurements on MAST using a midplane RFEA
Ion energy measurements have been made in the scrape off layer of the Mega
Amp Spherical Tokamak (MAST) using a midplane retarding field energy analyser
(RFEA) in H-mode plasmas during the inter-edge localised mode (ELM) period and
during type I and type III ELMs. During the inter-ELM period at distances of 3
to 8 cm from the last closed flux surface (LCFS), ion temperatures of 20 to 70
eV have been measured giving an ion to electron temperature ratio of 2 to 7
with a mean of 4. During type III ELMs, an ion temperature of 50 eV has been
measured 3 to 6 cm from the LCFS which decreases to 30 eV at distances 11 to 16
cm from the LCFS. During type I ELMs, an ion temperature of 40 eV has been
measured at a distance of 10 to 15 cm from the LCFS.Comment: 15 pages, 5 figure
Observations and modeling of the early acceleration phase of erupting filaments involved in coronal mass ejections
We examine the early phases of two near-limb filament destabilization
involved in coronal mass ejections on 16 June and 27 July 2005, using
high-resolution, high-cadence observations made with the Transition Region and
Coronal Explorer (TRACE), complemented by coronagraphic observations by Mauna
Loa and the SOlar and Heliospheric Observatory (SOHO). The filaments' heights
above the solar limb in their rapid-acceleration phases are best characterized
by a height dependence h(t) ~ t^m with m near, or slightly above, 3 for both
events. Such profiles are incompatible with published results for breakout,
MHD-instability, and catastrophe models. We show numerical simulations of the
torus instability that approximate this height evolution in case a substantial
initial velocity perturbation is applied to the developing instability. We
argue that the sensitivity of magnetic instabilities to initial and boundary
conditions requires higher fidelity modeling of all proposed mechanisms if
observations of rise profiles are to be used to differentiate between them. The
observations show no significant delays between the motions of the filament and
of overlying loops: the filaments seem to move as part of the overall coronal
field until several minutes after the onset of the rapid-acceleration phase.Comment: ApJ (2007, in press
Coherence loss and revivals in atomic interferometry: A quantum-recoil analysis
The coherence effects induced by external photons coupled to matter waves
inside a Mach-Zehnder three-grating interferometer are analyzed. Alternatively
to atom-photon entanglement scenarios, the model considered here only relies on
the atomic wave function and the momentum shift induced in it by the photon
scattering events. A functional dependence is thus found between the
observables, namely the fringe visibility and the phase shift, and the
transversal momentum transfer distribution. A good quantitative agreement is
found when comparing the results obtained from our model with the experimental
data.Comment: 18 pages, 4 figure
Measurement of Trace I-129 Concentrations in CsI Powder and Organic Liquid Scintillator with Accelerator Mass Spectrometry
Levels of trace radiopurity in active detector materials is a subject of
major concern in low-background experiments. Procedures were devised to measure
trace concentrations of I-129 in the inorganic salt CsI as well as in organic
liquid scintillator with Accelerator Mass Spectrometry (AMS) which leads to
improvement in sensitivities by several orders of magnitude over other methods.
No evidence of their existence in these materials were observed. Limits of < 6
X 10^{-13} g/g and < 2.6 X 10^{-17} g/g on the contaminations of I-129 in CsI
and liquid scintillator, respectively, were derived.These are the first results
in a research program whose goals are to develop techniques to measure trace
radioactivity in detector materials by AMS.Comment: Proceedings of 10th International Conference on Accelerator Mass
Spectrometr
Pliocene-Pleistocene evolution of sea surface and intermediate water temperatures from the southwest Pacific
This is the final version of the article. Available from the publisher via the DOI in this record.Over the last 5 million years, the global climate system has evolved toward a colder mean state,
marked by large-amplitude oscillations in continental ice volume. Equatorward expansion of polar waters
and strengthening temperature gradients have been detected. However, the response of the mid latitudes
and high latitudes of the Southern Hemisphere is not well documented, despite the potential importance for
climate feedbacks including sea ice distribution and low-high latitude heat transport. Here we reconstruct the
Pliocene-Pleistocene history of both sea surface and Antarctic Intermediate Water (AAIW) temperatures on
orbital time scales from Deep Sea Drilling Project Site 593 in the Tasman Sea, southwest Pacific. We confirm
overall Pliocene-Pleistocene cooling trends in both the surface ocean and AAIW, although the patterns are
complex. The Pliocene is warmer than modern, but our data suggest an equatorward displacement of the
subtropical front relative to present and a poleward displacement of the subantarctic front of the Antarctic
Circumpolar Current (ACC). Two main intervals of cooling, from ~3 Ma and ~1.5 Ma, are coeval with cooling
and ice sheet expansion noted elsewhere and suggest that equatorward expansion of polar water masses
also characterized the southwest Pacific through the Pliocene-Pleistocene. However, the observed trends in
sea surface temperature and AAIW temperature are not identical despite an underlying link to the ACC, and
intervals of unusual surface ocean warmth (~2 Ma) and large-amplitude variability in AAIW temperatures
(from ~1 Ma) highlight complex interactions between equatorward displacements of fronts associated with
the ACC and/or varying poleward heat transport from the subtropics.The new data presented here are stored
at the NOAA-National Climatic Data
Center (NCDC) paleoclimate repository
(available at https://www.ncdc.noaa.gov/
paleo/study/20225). This work
was supported by the UK Natural
Environment Research Council (awards
NE/I027703/1 and IP-1339-1112 to E.L.M.
and NE/I024372/1 to S.K.) and a Philip
Leverhulme Prize (awarded to E.L.M.).
This work was also funded (in part) by
The European Research Council (grant
2010-NEWLOG ADG-267931 (awarded to
H.E.). We thank Jessica Bownes, Martin
West, Benjamin Petrick, Joanne
Menegazzo, Hilary Sloane, and James
Rolfe for the laboratory support and
analytical assistance. We thank David
Evans and Stella Woodard for their
discussions, and two anonymous
reviewers for providing valuable comments
to improve the manuscript. This
research used samples provided by the
Integrated Ocean Drilling Program
(IODP), and we would like to thank the
Kochi IODP Core Center Repository for
the help with core sampling
Hinode Observations of Vector Magnetic Field Change Associated with a Flare on 2006 December 13
Continuous observations of a flare productive active region 10930 were
successfully carried out with the Solar Optical Telescope onboard the Hinode
spacecraft during 2007 December 6 to 19. We focus on the evolution of
photospheric magnetic fields in this active region, and magnetic field
properties at the site of the X3.4 class flare, using a time series of vector
field maps with high spatial resolution. The X3.4 class flare occurred on 2006
December 13 at the apparent collision site between the large, opposite polarity
umbrae. Elongated magnetic structures with alternatingly positive and negative
polarities resulting from flux emergence appeared one day before the flare in
the collision site penumbra. Subsequently, the polarity inversion line at the
collision site became very complicated. The number of bright loops in Ca II H
increased during the formation of these elongated magnetic structures. The
flare ribbons and bright loops evolved along the polarity inversion line and
one footpoint of the bright loop was located in a region having a large
departure of field azimuth angle with respect to its surroundings. The SOT
observations with high spatial resolution and high polarization precision
reveal temporal change in fine structure of magnetic fields at the flare site:
some parts of the complicated polarity inversion line then disappeared, and in
those regions the azimuth angle of photospheric magnetic field changed by about
90 degrees, becoming more spatially uniform within the collision site.Comment: 6 pages, 4 figures, accepted for publication in PASJ (Hinode Special
Issue
Characteristics of lesser prairie-chicken (Tympanuchus pallidicinctus) long-distance movements across their distribution
Citation: Earl, J. E., Fuhlendorf, S. D., Haukos, D., Tanner, A. M., Elmore, D., & Carleton, S. A. (2016). Characteristics of lesser prairie-chicken (Tympanuchus pallidicinctus) long-distance movements across their distribution. Ecosphere, 7(8). doi:10.1002/(ISSN)2150-8925Long-distance movements are important adaptive behaviors that contribute to population, community, and ecosystem connectivity. However, researchers have a poor understanding of the characteristics of long-distance movements for most species. Here, we examined long-distance movements for the lesser prairie-chicken (Tympanuchus pallidicinctus), a species of conservation concern. We addressed the following questions: (1) At what distances could populations be connected? (2) What are the characteristics and probability of dispersal movements? (3) Do lesser prairie-chickens display exploratory and round-trip movements? (4) Do the characteristics of long-distance movements vary by site? Movements were examined from populations using satellite GPS transmitters across the entire distribution of the species in New Mexico, Oklahoma, Kansas, and Colorado. Dispersal movements were recorded up to 71 km net displacement, much farther than hitherto recorded. These distances suggest that there may be greater potential connectivity among populations than previously thought. Dispersal movements were displayed primarily by females and had a northerly directional bias. Dispersal probabilities ranged from 0.08 to 0.43 movements per year for both sexes combined, although these movements averaged only 16 km net displacement. Lesser prairie-chickens displayed both exploratory foray loops and round-trip movements. Half of round-trip movements appeared seasonal, suggesting a partial migration in some populations. None of the long-distance movements varied by study site. Data presented here will be important in parameterizing models assessing population viability and informing conservation planning, although further work is needed to identify landscape features that may reduce connectivity among populations. © 2016 Earl et al
Assessing communication quality of consultations in primary care: initial reliability of the Global Consultation Rating Scale, based on the Calgary-Cambridge Guide to the Medical Interview.
OBJECTIVES: To investigate initial reliability of the Global Consultation Rating Scale (GCRS: an instrument to assess the effectiveness of communication across an entire doctor-patient consultation, based on the Calgary-Cambridge guide to the medical interview), in simulated patient consultations. DESIGN: Multiple ratings of simulated general practitioner (GP)-patient consultations by trained GP evaluators. SETTING: UK primary care. PARTICIPANTS: 21 GPs and six trained GP evaluators. OUTCOME MEASURES: GCRS score. METHODS: 6 GP raters used GCRS to rate randomly assigned video recordings of GP consultations with simulated patients. Each of the 42 consultations was rated separately by four raters. We considered whether a fixed difference between scores had the same meaning at all levels of performance. We then examined the reliability of GCRS using mixed linear regression models. We augmented our regression model to also examine whether there were systematic biases between the scores given by different raters and to look for possible order effects. RESULTS: Assessing the communication quality of individual consultations, GCRS achieved a reliability of 0.73 (95% CI 0.44 to 0.79) for two raters, 0.80 (0.54 to 0.85) for three and 0.85 (0.61 to 0.88) for four. We found an average difference of 1.65 (on a 0-10 scale) in the scores given by the least and most generous raters: adjusting for this evaluator bias increased reliability to 0.78 (0.53 to 0.83) for two raters; 0.85 (0.63 to 0.88) for three and 0.88 (0.69 to 0.91) for four. There were considerable order effects, with later consultations (after 15-20 ratings) receiving, on average, scores more than one point higher on a 0-10 scale. CONCLUSIONS: GCRS shows good reliability with three raters assessing each consultation. We are currently developing the scale further by assessing a large sample of real-world consultations
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