93 research outputs found
Jovian Auroral Ion Precipitation: X‐Ray Production From Oxygen and Sulfur Precipitation
Many attempts have been made to model X‐ray emission from both bremsstrahlung and ion precipitation into Jupiter's polar caps. Electron bremsstrahlung modeling has fallen short of producing the total overall power output observed by Earth‐orbit‐based X‐ray observatories. Heavy ion precipitation was able to reproduce strong X‐ray fluxes, but the proposed incident ion energies were very high ( urn:x-wiley:jgra:media:jgra55396:jgra55396-math-00011 MeV per nucleon). Now with the Juno spacecraft at Jupiter, there have been many measurements of heavy ion populations above the polar cap with energies up to 300–400 keV per nucleon (keV/u), well below the ion energies required by earlier models. Recent work has provided a new outlook on how ion‐neutral collisions in the Jovian atmosphere are occurring, providing us with an entirely new set of impact cross sections. The model presented here simulates oxygen and sulfur precipitation, taking into account the new cross sections, every collision process, the measured ion fluxes above Jupiter's polar aurora, and synthetic X‐ray spectra. We predict X‐ray fluxes, efficiencies, and spectra for various initial ion energies considering opacity effects from two different atmospheres. We demonstrate that an in situ measured heavy ion flux above Jupiter's polar cap is capable of producing over 1 GW of X‐ray emission when some assumptions are made. Comparison of our approximated synthetic X‐ray spectrum produced from in situ particle data with a simultaneous X‐ray spectrum observed by XMM‐Newton shows good agreement for the oxygen part of the spectrum but not for the sulfur part
Intervals of Intense Energetic Electron Beams Over Jupiter's Poles
Juno's Jupiter Energetic particle Detector Instrument often detects energetic electron beams over Jupiter's polar regions. In this paper, we document a subset of intense magnetic field‐aligned beams of energetic electrons moving away from Jupiter at high magnetic latitudes both north and south of the planet. The number fluxes of these beams are often dominated by electrons with energies above about 1 MeV. These very narrow beams can create broad angular responses in the Jupiter Energetic particle Detector Instrument with unique signatures in the detector count rates, probably because of >10 MeV electrons. We use these signatures to identify the most intense beams. These beams occur primarily above the swirl region of the polar cap aurora. This polar region is described as being of low brightness and high absorption and the most magnetically “open” at Jupiter
The breadth of primary care: a systematic literature review of its core dimensions
Background: Even though there is general agreement that primary care is the linchpin of effective health care delivery, to date no efforts have been made to systematically review the scientific evidence supporting this supposition. The aim of this study was to examine the breadth of primary care by identifying its core dimensions and to assess the evidence for their interrelations and their relevance to outcomes at (primary) health system level.
Methods: A systematic review of the primary care literature was carried out, restricted to English language journals reporting original research or systematic reviews. Studies published between 2003 and July 2008 were searched in MEDLINE, Embase, Cochrane Library, CINAHL, King's Fund Database, IDEAS Database, and EconLit.
Results: Eighty-five studies were identified. This review was able to provide insight in the complexity of primary care as a multidimensional system, by identifying ten core dimensions that constitute a primary care system. The structure of a primary care system consists of three dimensions: 1. governance; 2. economic conditions; and 3. workforce development. The primary care process is determined by four dimensions: 4. access; 5. continuity of care; 6. coordination of care; and 7. comprehensiveness of care. The outcome of a primary care system includes three dimensions: 8. quality of care; 9. efficiency care; and 10. equity in health. There is a considerable evidence base showing that primary care contributes through its dimensions to overall health system performance and health.
Conclusions: A primary care system can be defined and approached as a multidimensional system contributing to overall health system performance and health
Search for New Physics in e mu X Data at D0 Using Sleuth: A Quasi-Model-Independent Search Strategy for New Physics
We present a quasi-model-independent search for the physics responsible for
electroweak symmetry breaking. We define final states to be studied, and
construct a rule that identifies a set of relevant variables for any particular
final state. A new algorithm ("Sleuth") searches for regions of excess in those
variables and quantifies the significance of any detected excess. After
demonstrating the sensitivity of the method, we apply it to the semi-inclusive
channel e mu X collected in 108 pb^-1 of ppbar collisions at sqrt(s) = 1.8 TeV
at the D0 experiment during 1992-1996 at the Fermilab Tevatron. We find no
evidence of new high p_T physics in this sample.Comment: 23 pages, 12 figures. Submitted to Physical Review
Ratio of the Isolated Photon Cross Sections at \sqrt{s} = 630 and 1800 GeV
The inclusive cross section for production of isolated photons has been
measured in \pbarp collisions at GeV with the \D0 detector at
the Fermilab Tevatron Collider. The photons span a transverse energy ()
range from 7-49 GeV and have pseudorapidity . This measurement is
combined with to previous \D0 result at GeV to form a ratio
of the cross sections. Comparison of next-to-leading order QCD with the
measured cross section at 630 GeV and ratio of cross sections show satisfactory
agreement in most of the range.Comment: 7 pages. Published in Phys. Rev. Lett. 87, 251805, (2001
Quasi-model-independent search for new high physics at D0
We apply a quasi-model-independent strategy ("Sleuth") to search for new high p_T physics in approximately 100 pb^-1 of ppbar collisions at sqrt(s) = 1.8 TeV collected by the DZero experiment during 1992-1996 at the Fermilab Tevatron. We systematically analyze many exclusive final states and demonstrate sensitivity to a variety of models predicting new phenomena at the electroweak scale. No evidence of new high p_T physics is observed
Search for single top quark production at D0 using neural networks
We present a search for electroweak production of single top quarks in ~90 pb^-1 of data collected with the DZero detector at the Fermilab Tevatron collider. Using arrays of neural networks to separate signals from backgrounds, we set upper limits on the cross sections of 17 pb for the s-channel process ppbar->tb+X, and 22 pb for the t-channel process ppbar->tqb+X, both at the 95% confidence level
Cross Section for b Jet Production in pbar-p Collisions at sqrt(s) = 1.8 TeV
Bottom quark production in pbar-p collisions at sqrt(s)=1.8 TeV is studied
with 5 inverse picobarns of data collected in 1995 by the DO detector at the
Fermilab Tevatron Collider. The differential production cross section for b
jets in the central rapidity region (|y(b)| < 1) as a function of jet
transverse energy is extracted from a muon-tagged jet sample. Within
experimental and theoretical uncertainties, DO results are found to be higher
than, but compatible with, next-to-leading-order QCD predictions.Comment: 11 pages, 3 figure
Small Angle Muon and Bottom Quark Production in pbarp Collisions at sqrt(s) = 1.8 TeV
This Letter describes a measurement of the muon cross section originating
from b quark decay in the forward rapidity range 2.4 < y(mu) < 3.2 in pbarp
collisions at sqrt(s) = 1.8 TeV. The data used in this analysis were collected
by the D0 experiment at the Fermilab Tevatron. We find that NLO QCD
calculations underestimate b quark production by a factor of four in the
forward rapidity region. A cross section measurement using muon+jet data has
been included in this version of the paper.Comment: 12 pages, 5 figures, submitted to PR
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