875 research outputs found
Circulation first â the time has come to question the sequencing of care in the ABCs of trauma; an American Association for the Surgery of Trauma multicenter trial
Background The traditional sequence of trauma care: Airway, Breathing, Circulation (ABC) has been practiced for many years. It became the standard of care despite the lack of scientific evidence. We hypothesized that patients in hypovolemic shock would have comparable outcomes with initiation of bleeding treatment (transfusion) prior to intubation (CAB), compared to those patients treated with the traditional ABC sequence. Methods This study was sponsored by the American Association for the Surgery of Trauma multicenter trials committee. We performed a retrospective analysis of all patients that presented to trauma centers with presumptive hypovolemic shock indicated by pre-hospital or emergency department hypotension and need for intubation from January 1, 2014 to July 1, 2016. Data collected included demographics, timing of intubation, vital signs before and after intubation, timing of the blood transfusion initiation related to intubation, and outcomes. Results From 440 patients that met inclusion criteria, 245 (55.7%) received intravenous blood product resuscitation first (CAB), and 195 (44.3%) were intubated before any resuscitation was started (ABC). There was no difference in ISS, mechanism, or comorbidities. Those intubated prior to receiving transfusion had a lower GCS than those with transfusion initiation prior to intubation (ABC: 4, CAB:9, pâ=â0.005). Although mortality was high in both groups, there was no statistically significant difference (CAB 47% and ABC 50%). In multivariate analysis, initial SBP and initial GCS were the only independent predictors of death. Conclusion The current study highlights that many trauma centers are already initiating circulation first prior to intubation when treating hypovolemic shock (CAB), even in patients with a low GCS. This practice was not associated with an increased mortality. Further prospective investigation is warranted. Trial registration IRB approval number: HM20006627. Retrospective trial not registered
Observations of a Newly "Captured" Magnetosheath Field Line: Evidence for "Double Reconnection"
We have begun an investigation of the nature of the low-latitude boundary layer in the mid-altitude cusp region using data from the Polar spacecraft. This region has been routinely sampled for about three months each year for the periods 1999-2001 and 2004-2006. The low-to-mid-energy ion instruments frequently observed dense, magnetosheath-like plasma deep (in terms of distance from the magnetopause and in invariant latitude) in the magnetosphere. One such case, taken during a period of northward interplanetary magnetic field (IMF), shows magnetosheath ions within the magnetosphere with velocity distributions resulting from two separate merging sites along the same field lines. Cold ionospheric ions were also observed counterstreaming along the field lines, evidence that these field lines were closed. These results are consistent with the hypothesis that double merging can produce closed field .lines populated by solar wind plasma. Through the use of individual cases such as this and statistical studies of a broader database we seek to understand the morphology of the LLBL as it projects from the sub-solar region into the cusp. We will present preliminary results of our ongoing study
Measurements of dense fuel hydrodynamics in the NIF burning plasma experiments using backscattered neutron spectroscopy
The hydrodynamics of the dense confining fuel shell is of great importance in
defining the behaviour of the burning plasma and burn propagation regimes of
inertial confinement fusion experiments. However, it is difficult to probe due
to its low emissivity in comparison to the central fusion core. In this work,
we utilise the backscattered neutron spectroscopy technique to directly measure
the hydrodynamic conditions of the dense fuel during fusion burn. Experimental
data is fit to obtain dense fuel velocities and apparent ion temperatures.
Trends of these inferred parameters with yield and velocity of the burning
plasma are used to investigate their dependence on alpha heating and low mode
drive asymmetry. It is shown that the dense fuel layer has an increased outward
radial velocity as yield increases showing burn has continued into
re-expansion, a key signature of hotspot ignition. Comparison with analytic and
simulation models show that the observed dense fuel parameters are displaying
signatures of burn propagation into the dense fuel layer, including a rapid
increase in dense fuel apparent ion temperature with neutron yield
Atmospheric carbon dioxide variability in the Community Earth System Model : evaluation and transient dynamics during the twentieth and twenty-first centuries
Author Posting. © American Meteorological Society, 2013. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 26 (2013): 4447â4475, doi:10.1175/JCLI-D-12-00589.1.Changes in atmospheric CO2 variability during the twenty-first century may provide insight about ecosystem responses to climate change and have implications for the design of carbon monitoring programs. This paper describes changes in the three-dimensional structure of atmospheric CO2 for several representative concentration pathways (RCPs 4.5 and 8.5) using the Community Earth System ModelâBiogeochemistry (CESM1-BGC). CO2 simulated for the historical period was first compared to surface, aircraft, and column observations. In a second step, the evolution of spatial and temporal gradients during the twenty-first century was examined. The mean annual cycle in atmospheric CO2 was underestimated for the historical period throughout the Northern Hemisphere, suggesting that the growing season net flux in the Community Land Model (the land component of CESM) was too weak. Consistent with weak summer drawdown in Northern Hemisphere high latitudes, simulated CO2 showed correspondingly weak northâsouth and vertical gradients during the summer. In the simulations of the twenty-first century, CESM predicted increases in the mean annual cycle of atmospheric CO2 and larger horizontal gradients. Not only did the mean northâsouth gradient increase due to fossil fuel emissions, but eastâwest contrasts in CO2 also strengthened because of changing patterns in fossil fuel emissions and terrestrial carbon exchange. In the RCP8.5 simulation, where CO2 increased to 1150 ppm by 2100, the CESM predicted increases in interannual variability in the Northern Hemisphere midlatitudes of up to 60% relative to present variability for time series filtered with a 2â10-yr bandpass. Such an increase in variability may impact detection of changing surface fluxes from atmospheric observations.The CESM project is supported
by the National Science Foundation and the Office of
Science (BER) of the U.S. Department of Energy.
Computing resources were provided by the Climate
Simulation Laboratory at NCARâs Computational and
Information Systems Laboratory (CISL), sponsored by
the National Science Foundation and other agencies.
G.K.A. acknowledges support of a NOAA Climate and
Global Change postdoctoral fellowship. J.T.R., N.M.M.,
S.C.D., K.L., and J.K.M. acknowledge support of Collaborative
Research: Improved Regional and Decadal
Predictions of the Carbon Cycle (NSF AGS-1048827,
AGS-1021776,AGS-1048890). TheHIPPO Programwas
supported byNSF GrantsATM-0628575,ATM-0628519,
and ATM-0628388 to Harvard University, University of
California (San Diego), and by University Corporation
for Atmospheric Research, University of Colorado/
CIRES, by the NCAR and by the NOAAEarth System
Research Laboratory. Sunyoung Park, Greg Santoni,
Eric Kort, and Jasna Pittman collected data during
HIPPO. The ACME project was supported by the Office
of Biological and Environmental Research of the U.S.
Department of Energy under Contract DE-AC02-
05CH11231 as part of the Atmospheric Radiation Measurement
Program (ARM), the ARM Aerial Facility,
and the Terrestrial EcosystemScience Program. TCCON
measurements at Eureka were made by the Canadian
Network for Detection of Atmospheric Composition
Change (CANDAC) with additional support from the
Canadian Space Agency. The Lauder TCCON program
was funded by the New Zealand Foundation for Research
Science and Technology contracts CO1X0204,
CO1X0703, and CO1X0406. Measurements at Darwin
andWollongong were supported by Australian Research
Council Grants DP0879468 and DP110103118 and
were undertaken by David Griffith, Nicholas Deutscher,
and Ronald Macatangay. We thank Pauli Heikkinen,
Petteri Ahonen, and Esko KyrâŹo of the Finnish Meteorological
Institute for contributing the SodankylâŹa
TCCON data. Measurements at Park Falls, Lamont, and
Pasadena were supported byNASAGrant NNX11AG01G
and the NASA Orbiting Carbon Observatory Program.
Data at these sites were obtained by Geoff Toon, Jean-
Francois Blavier, Coleen Roehl, and Debra Wunch.2014-01-0
Two-sided bounds on minimum-error quantum measurement, on the reversibility of quantum dynamics, and on the maximum overlap problem using directional iterates
In a unified framework, we obtain two-sided estimates of the following
quantities of interest in quantum information theory:
1.The minimum-error distinguishability of arbitrary ensembles of mixed
quantum states.
2.The approximate reversibility of quantum dynamics in terms of entanglement
fidelity. (This is also referred to as "channel-adapted quantum error recovery"
when the reversed channel is the composition of an encoding operation and a
noise channel.)
3.The maximum overlap between a bipartite pure quantum state and a bipartite
mixed state that may be achieved by applying a local quantum operation to one
part of the mixed state.
4. The conditional min-entropy of bipartite quantum states.
A refined version of the author's techniques [J. Math. Phys. 50, 032016] for
bounding the first quantity is employed to give two-sided estimates of the
remaining three quantities. Our primary tool is "small angle" initialization of
an abstract generalization of the iterative schemes for computing optimal
measurements and quantum error recoveries introduced by Jezek-Rehacek-Fiurasek
[Phys. Rev. A 65, 060301], Jezek-Fiurasek-Hradil [Phys. Rev. A 68, 012305], and
Reimpell-Werner [Phys. Rev. Lett 94, 080501].Comment: Extensively revised & new content added. Improved min-entropy bounds.
Notation made more accessible. Minimax theorem used to clarify relationship
between "worst case" bounds and "single instance" bounds. Improved motivation
of the choice of "small angle" guess. Eliminated spurious factor appearing
when overlap bounds are applied to state distinction. Work connected to that
of Beny and Oreshko
International home economics
The conference was planned to serve the interests of those who wish to work in home economics programs abroad and those who are concerned with the education of international students in the universities and colleges of the United States. Approximately 165 home economists from other states and from foreign countries I including the African and Latin American countries I participated in the conference.https://lib.dr.iastate.edu/card_reports/1026/thumbnail.jp
Evidence for t\bar{t}\gamma Production and Measurement of \sigma_t\bar{t}\gamma / \sigma_t\bar{t}
Using data corresponding to 6.0/fb of ppbar collisions at sqrt(s) = 1.96 TeV
collected by the CDF II detector, we present a cross section measurement of
top-quark pair production with an additional radiated photon. The events are
selected by looking for a lepton, a photon, significant transverse momentum
imbalance, large total transverse energy, and three or more jets, with at least
one identified as containing a b quark. The ttbar+photon sample requires the
photon to have 10 GeV or more of transverse energy, and to be in the central
region. Using an event selection optimized for the ttbar+photon candidate
sample we measure the production cross section of, and the ratio of cross
sections of the two samples. Control samples in the dilepton+photon and
lepton+photon+\met, channels are constructed to aid in decay product
identification and background measurements. We observe 30 ttbar+photon
candidate events compared to the standard model expectation of 26.9 +/- 3.4
events. We measure the ttbar+photon cross section to be 0.18+0.08 pb, and the
ratio of the cross section of ttbar+photon to ttbar to be 0.024 +/- 0.009.
Assuming no ttbar+photon production, we observe a probability of 0.0015 of the
background events alone producing 30 events or more, corresponding to 3.0
standard deviations.Comment: 9 pages, 3 figure
Search for the Higgs boson in events with missing transverse energy and b quark jets produced in proton-antiproton collisions at s**(1/2)=1.96 TeV
We search for the standard model Higgs boson produced in association with an
electroweak vector boson in events with no identified charged leptons, large
imbalance in transverse momentum, and two jets where at least one contains a
secondary vertex consistent with the decay of b hadrons. We use ~1 fb-1
integrated luminosity of proton-antiproton collisions at s**(1/2)=1.96 TeV
recorded by the CDF II experiment at the Tevatron. We find 268 (16) single
(double) b-tagged candidate events, where 248 +/- 43 (14.4 +/- 2.7) are
expected from standard model background processes. We place 95% confidence
level upper limits on the Higgs boson production cross section for several
Higgs boson masses ranging from 110 GeV/c2 to 140 GeV/c2. For a mass of 115
GeV/c2 the observed (expected) limit is 20.4 (14.2) times the standard model
prediction.Comment: 8 pages, 2 figures, submitted to Phys. Rev. Let
Precision Top-Quark Mass Measurements at CDF
We present a precision measurement of the top-quark mass using the full
sample of Tevatron TeV proton-antiproton collisions collected
by the CDF II detector, corresponding to an integrated luminosity of 8.7
. Using a sample of candidate events decaying into the
lepton+jets channel, we obtain distributions of the top-quark masses and the
invariant mass of two jets from the boson decays from data. We then compare
these distributions to templates derived from signal and background samples to
extract the top-quark mass and the energy scale of the calorimeter jets with
{\it in situ} calibration. The likelihood fit of the templates from signal and
background events to the data yields the single most-precise measurement of the
top-quark mass, \mtop = 172.85 \pm\pmComment: submitted to Phys. Rev. Let
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