152 research outputs found
Kinematic Orbits and the Structure of the Internal Space for Systems of Five or More Bodies
The internal space for a molecule, atom, or other n-body system can be
conveniently parameterised by 3n-9 kinematic angles and three kinematic
invariants. For a fixed set of kinematic invariants, the kinematic angles
parameterise a subspace, called a kinematic orbit, of the n-body internal
space. Building on an earlier analysis of the three- and four-body problems, we
derive the form of these kinematic orbits (that is, their topology) for the
general n-body problem. The case n=5 is studied in detail, along with the
previously studied cases n=3,4.Comment: 38 pages, submitted to J. Phys.
Wide-bandwidth, tunable, multiple-pulse-width optical delays using slow light in cesium vapor
We demonstrate an all-optical delay line in hot cesium vapor that tunably
delays 275 ps input pulses up to 6.8 ns and 740 input ps pulses up to 59 ns
(group index of approximately 200) with little pulse distortion. The delay is
made tunable with a fast reconfiguration time (hundreds of ns) by optically
pumping out of the atomic ground states.Comment: 4 pages, 6 figure
Health Workers’ Perceptions on Where and How to Integrate Tobacco Use Cessation Services Into Tuberculosis Treatment; A Qualitative Exploratory Study in Uganda
Background: Tobacco use is associated with exacerbation of tuberculosis (TB) and poor TB treatment outcomes. Integrating tobacco use cessation within TB treatment could improve healing among TB patients. The aim was to explore perceptions of health workers on where and how to integrate tobacco use cessation services into TB treatment programs in Uganda. Methods: Between March and April 2019, nine focus group discussions (FGDs) and eight key informant interviews were conducted among health workers attending to patients with tuberculosis on a routine basis in nine facilities from the central, eastern, northern and western parts of Uganda. These facilities were high volume health centres, general hospitals and referral hospitals. The FGD sessions and interviews were tape recorded, transcribed verbatim and analysed using content analysis and the Chronic Care Model as a framework. Results: Respondents highlighted that just like TB prevention starts in the community and TB treatment goes beyond health facility stay, integration of tobacco cessation should be started when people are still healthy and extended to those who have been healed as they go back to communities. There was need to coordinate with different organizations like peers, the media and TB treatment supporters. TB patients needed regular follow up and self-management support for both TB and tobacco cessation. Patients needed to be empowered to know their condition and their caretakers needed to be involved. Effective referral between primary health facilities and specialist facilities was needed. Clinical information systems should identify relevant people for proactive care and follow up. In order to achieve effective integration, the health system needed to be strengthened especially health worker training and provision of more space in some of the facilities. Conclusions: Tobacco cessation activities should be provided in a continuum starting in the community before the TB patients get to hospital, during the patients’ interface with hospital treatment and be given in the community after TB patients have been discharged. This requires collaboration between those who carry out health education in communities, the TB treatment supporters and the health workers who treat patients in health facilities
Wide-Bandwidth, Tunable, Multiple-Pulse-Width Optical Delays Using Slow Light in Cesium Vapor
We demonstrate an all-optical delay line in hot cesium vapor that tunably delays 275 ps input pulses up to 6.8 ns and 740 input ps pulses up to 59 ns (group index of approximately 200) with little pulse distortion. The delay is made tunable with a fast reconfiguration time (hundreds of ns) by optically pumping out of the atomic ground states
Trait Hope and Preparation for Future Care Needs among Older Adult Primary Care Patients
We examined associations between trait hope and preparation for future care needs (PFCN) among 66 older adult primary care patients in western New York. Participants completed a questionnaire assessing PFCN (awareness, information gathering, decision-making, concrete planning, and avoidance), and the Adult Trait Hope Scale. In multivariate regressions, lower hope, particularly less agency, was associated with more awareness of needing care, whereas higher hopefulness, particularly pathways thinking, was associated with increased decision-making and concrete planning. Greater hopefulness appears to be linked to goal-directed planning behaviors, although those with lower hope may actually be more aware of the need for planning. Evidence-based programming that encourages learned hopefulness may contribute to enhanced health planning and decision-making among older adult primary care patients
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Robotically Enhanced Advanced Manufacturing Concepts to Optimize Energy, Productivity, and Environmental Performance
In the first phase of the REML project, major assets were acquired for a manufacturing line for follow-on installation, capability studies and optimization. That activity has been documented in the DE-FC36-99ID13819 final report. In this the second phase of the REML project, most of the major assets have been installed in a manufacturing line arrangement featuring a green cell, a thermal treatment cell and a finishing cell. Most of the secondary and support assets have been acquired and installed. Assets have been integrated with a commercial, machine-tending gantry robot in the thermal treatment cell and with a low-mass, high-speed gantry robot in the finish cell. Capabilities for masterless gauging of product’s dimensional and form characteristics were advanced. Trial production runs across the entire REML line have been undertaken. Discrete event simulation modeling has aided in line balancing and reduction of flow time. Energy, productivity and cost, and environmental comparisons to baselines have been made. Energy The REML line in its current state of development has been measured to be about 22% (338,000 kVA-hrs) less energy intensive than the baseline conventional low volume line assuming equivalent annual production volume of approximately 51,000 races. The reduction in energy consumption is largely attributable to the energy reduction in the REML thermal treatment cell where the heating devices are energized on demand and are appropriately sized to the heating load of a near single piece flow line. If additional steps such as power factor correction and use of high-efficiency motors were implemented to further reduce energy consumption, it is estimated, but not yet demonstrated, that the REML line would be about 30% less energy intensive than the baseline conventional low volume line assuming equivalent annual production volume. Productivity The capital cost of an REML line would be roughly equivalent to the capital cost of a new conventional line. The unit raw material cost for REML (through-hardened bearing steel) is somewhat greater than raw material cost for the conventional line (case-hardened bearing steel). However, changeover time, tooling costs, gauging costs, utilities and energy costs, and manning of REML are less than the conventional line. Since REML supports near single piece flow, work in process inventory and work flow time are much less on the REML line than on the conventional line. REML allows the reduction in inventory of source steel tube sizes from several hundred to a few dozen. As a result, the business model indicates that the costs incurred on the manufacturing line are less with the REML line than with the conventional line for low manufacturing run volumes. Environment The REML line, when processing through-hardenable steel, requires far less hydrocarbon and other process gases than the conventional line when processing case hardenable steel. The REML line produces fewer greenhouse gas emissions and less liquid and solid waste materials. Broad Applicability The REML benefits will in general be extendible to the manufacture of non-bearing, heat treated and finished machined metal parts in the United States
Triple oxygen isotopic composition of the high-<sup>3</sup>He/<sup>4</sup>He mantle
Measurements of Xe isotope ratios in ocean island basalts (OIB) suggest that Earth’s mantle accreted heterogeneously, and that compositional remnants of accretion are sampled by modern, high-3He/4He OIB associated with the Icelandic and Samoan plumes. If so, the high-3He/4He source may also have a distinct oxygen isotopic composition from the rest of the mantle. Here, we test if the major elements of the high-3He/4He source preserve any evidence of heterogeneous accretion using measurements of three oxygen isotopes on olivine from a variety of high-3He/4He OIB locations. To high precision, the Δ17O value of high-3He/4He olivines from Hawaii, Pitcairn, Baffin Island and Samoa, are indistinguishable from bulk mantle olivine (Δ17OBulk Mantle − Δ17OHigh 3He/4He olivine = −0.002 ± 0.004 (2 × SEM)‰). Thus, there is no resolvable oxygen isotope evidence for heterogeneous accretion in the high-3He/4He source. Modelling of mixing processes indicates that if an early-forming, oxygen-isotope distinct mantle did exist, either the anomaly was extremely small, or the anomaly was homogenised away by later mantle convection.
The δ18O values of olivine with the highest 3He/4He ratios from a variety of OIB locations have a relatively uniform composition (∼5‰). This composition is intermediate to values associated with the depleted MORB mantle and the average mantle. Similarly, δ18O values of olivine from high-3He/4He OIB correlate with radiogenic isotope ratios of He, Sr, and Nd. Combined, this suggests that magmatic oxygen is sourced from the same mantle as other, more incompatible elements and that the intermediate δ18O value is a feature of the high-3He/4He mantle source. The processes responsible for the δ18O signature of high-3He/4He mantle are not certain, but δ18O–87Sr/86Sr correlations indicate that it may be connected to a predominance of a HIMU-like (high U/Pb) component or other moderate δ18O components recycled into the high-3He/4He source
Boundary Conditions on Internal Three-Body Wave Functions
For a three-body system, a quantum wave function with definite
and quantum numbers may be expressed in terms of an internal wave
function which is a function of three internal coordinates. This
article provides necessary and sufficient constraints on to
ensure that the external wave function is analytic. These
constraints effectively amount to boundary conditions on and its
derivatives at the boundary of the internal space. Such conditions find
similarities in the (planar) two-body problem where the wave function (to
lowest order) has the form at the origin. We expect the boundary
conditions to prove useful for constructing singularity free three-body basis
sets for the case of nonvanishing angular momentum.Comment: 41 pages, submitted to Phys. Rev.
The <i>Castalia</i> mission to Main Belt Comet 133P/Elst-Pizarro
We describe Castalia, a proposed mission to rendezvous with a Main Belt Comet (MBC), 133P/Elst-Pizarro. MBCs are a recently discovered population of apparently icy bodies within the main asteroid belt between Mars and Jupiter, which may represent the remnants of the population which supplied the early Earth with water. Castalia will perform the first exploration of this population by characterising 133P in detail, solving the puzzle of the MBC’s activity, and making the first in situ measurements of water in the asteroid belt. In many ways a successor to ESA’s highly successful Rosetta mission, Castalia will allow direct comparison between very different classes of comet, including measuring critical isotope ratios, plasma and dust properties. It will also feature the first radar system to visit a minor body, mapping the ice in the interior. Castalia was proposed, in slightly different versions, to the ESA M4 and M5 calls within the Cosmic Vision programme. We describe the science motivation for the mission, the measurements required to achieve the scientific goals, and the proposed instrument payload and spacecraft to achieve these
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