371 research outputs found
Barriers and facilitators to chemotherapy patients' engagement in medical error prevention
Background: Medical errors are a serious threat to chemotherapy patients. Patients can make contributions to safety but little is known about the acceptability of error-preventing behaviors and its predictors. Patients and methods: A cross-sectional survey study among chemotherapy patients treated at the oncology/hematology unit of a regional hospital was conducted. Patients were presented vignettes of errors and unsafe acts and responded to measures of attitudes, behavioral control, norms, barriers, and anticipated reaction. Results: A total of 479 patients completed the survey (52% response rate). Patients reported a high level of anticipated activity but intentions to engage for safety varied considerably between the hypothetical scenarios (range: 57%-96%, χ2 P < 0.001). Health, knowledge and staff time pressure were perceived as most important barriers. Instrumental [odds ratio (OR) = 1.3, P = 0.046] and experiential attitudes (OR = 1.4, P < 0.001), expectations attributed to clinical staff (OR = 1.2, P = 0.024) and behavioral control (OR = 1.8, P < 0.001) were predictors for patients' behaviors. Conclusions: Patients are affirmative toward engaging for safety but perceive considerable barriers. Intentions to engage in error prevention vary by clinical context and are strongly influenced by attitudes, normative and control beliefs. To successfully involve patients in medical error, prevention clinicians need to address their patients' beliefs and reduce barriers through educatio
The rotational excitation of HCN and HNC by He: New insights on the HCN/HNC abundance ratio in molecular clouds
Modeling of molecular emission from interstellar clouds requires the
calculation of rates for excitation by collisions with the most abundant
species. The present paper focuses on the calculation of rate coefficients for
rotational excitation of the HCN and HNC molecules in their ground vibrational
state in collision with He. The calculations are based on new two-dimensional
potential energy surfaces obtained from highly correlated \textit{ab initio}
calculations. Calculations of pure rotational (de)excitation cross sections of
HCN and HNC by He were performed using the essentially exact close-coupling
method. Cross sections for transitions among the 8 first rotational levels of
HCN and HNC were calculated for kinetic energies up to 1000 cm. These
cross sections were used to determine collisional rate constants for
temperatures ranging from 5 K to 100 K. A propensity for even
transitions is observed in the case of HCN--He collisions whereas a propensity
for odd transitions is observed in the case of HNC--He collisions.
The consequences for astrophysical models are evaluated and it is shown that
the use of HCN rate coefficients to interpret HNC observations can lead to
significant inaccuracies in the determination of the HNC abundance, in
particular in cold dark clouds for which the new HNC rates show that the
line of this species will be more easily excited by collisions than
HCN. An important result of the new HNC-He rates is that the HNC/HCN abundance
ratio derived from observations in cold clouds has to be revised from 1 to
1, in good agreement with detailed chemical models available in the
literature.Comment: 8 figue
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Seasonality and extent of extratropical TST derived from in-situ CO measurements during SPURT
International audienceWe present airborne in-situ trace gas measurements which were performed on eight campaigns between November 2001 and July 2003 during the SPURT-project (SPURenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region). The measurements on a quasi regular basis allowed an overview on the seasonal variations of the trace gas distribution in the tropopause region over Europe from 35°?75° N to investigate the influence of transport and mixing across the extratropical tropopause on the lowermost stratosphere. From the correlation of CO and O3 irreversible mixing of tropospheric air into the lowermost stratosphere is identified. The CO distribution indicates that transport and subsequent mixing of tropospheric air across the extratropical tropopause predominantely affects a layer, which closely follows the shape of the local tropopause. In addition the seasonal cycle of CO2 illustrates the strong coupling of that layer to the extratropical troposphere. Both, horizontal gradients of CO on isentropes as well as the CO-O3-distribution in the lowermost stratosphere reveal that the influence of quasi-horizontal transport and subsequent mixing weakens with distance from the local tropopause. However, at large distances from the tropopause a significant influence of tropospheric air is still evident. The relation between N2O and CO2 indicates that a significant contribution of air originating from the tropical tropopause contributes to the background air in the extratropical lowermost stratosphere
Analysis of a jet stream induced gravity wave associated with an observed ice cloud over Greenland
International audienceA polar stratospheric ice cloud (PSC type II) was observed by airborne lidar above Greenland on 14 January 2000. It was the unique observation of an ice cloud over Greenland during the SOLVE/THESEO 2000 campaign. Mesoscale simulations with the hydrostatic HRM model are presented which, in contrast to global analyses, are capable to produce a vertically propagating gravity wave that induces the low temperatures at the level of the PSC afforded for the ice formation. The simulated minimum temperature is ~8 K below the driving analyses and ~4.5 K below the frost point, exactly coinciding with the location of the observed ice cloud. Despite the high elevations of the Greenland orography the simulated gravity wave is not a mountain wave. Analyses of the horizontal wind divergence, of the background wind profiles, of backward gravity wave ray-tracing trajectories, of HRM experiments with reduced Greenland topography and of several diagnostics near the tropopause level provide evidence that the wave is emitted from an intense, rapidly evolving, anticyclonically curved jet stream. The precise physical process responsible for the wave emission could not be identified definitely, but geostrophic adjustment and shear instability are likely candidates. In order to evaluate the potential frequency of such non-orographic polar stratospheric cloud events, the non-linear balance equation diagnostic is performed for the winter 1999/2000. It indicates that ice-PSCs are only occasionally generated by gravity waves emanating from spontaneous adjustment
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Seasonal cycles and variability of O3 and H2O in the UT/LMS during SPURT
Airborne high resolution in situ measurements of a large set of trace gases including ozone (O3) and total water (H2O) in the upper troposphere and the lowermost stratosphere (UT/LMS) have been performed above Europe within the SPURT project. SPURT provides an extensive data coverage of the UT/LMS in each season within the time period between November 2001 and July 2003.
In the LMS a distinct spring maximum and autumn minimum is observed in O3, whereas its annual cycle in the UT is shifted by 2–3 months later towards the end of the year. The more variable H2O measurements reveal a maximum during summer and a minimum during autumn/winter with no phase shift between the two atmospheric compartments.
For a comprehensive insight into trace gas composition and variability in the UT/LMS several statistical methods are applied using chemical, thermal and dynamical vertical coordinates. In particular, 2-dimensional probability distribution functions serve as a tool to transform localised aircraft data to a more comprehensive view of the probed atmospheric region. It appears that both trace gases, O3 and H2O, reveal the most compact arrangement and are best correlated in the view of potential vorticity (PV) and distance to the local tropopause, indicating an advanced mixing state on these surfaces. Thus, strong gradients of PV seem to act as a transport barrier both in the vertical and the horizontal direction. The alignment of trace gas isopleths reflects the existence of a year-round extra-tropical tropopause transition layer. The SPURT measurements reveal that this layer is mainly affected by stratospheric air during winter/spring and by tropospheric air during autumn/summer.
Normalised mixing entropy values for O3 and H2O in the LMS appear to be maximal during spring and summer, respectively, indicating highest variability of these trace gases during the respective seasons
OASIS High-Resolution Integral Field Spectroscopy of the SAURON Ellipticals and Lenticulars
We present a summary of high-spatial resolution follow-up observations of the
elliptical (E) and lenticular (S0) galaxies in the SAURON survey using the
OASIS integral field spectrograph. The OASIS observations explore the central
8x10" regions of these galaxies using a spatial sampling four times higher than
SAURON, often revealing previously undiscovered features. Around 75% (31/48) of
the SAURON E/S0s with central velocity dispersion >= 120 km/s were observed
with OASIS, covering well the original SAURON representative sample. We present
here an overview of this follow-up survey, and some preliminary results on
individual objects, including a previously unreported counter-rotating core in
NGC 4382; the decoupled stellar and gas velocity fields of NGC 2768; and the
strong age gradient towards the centre of NGC 3489.Comment: 4 pages, 5 figures. Accepted for publication in Astron. Nachr. as
refereed proceedings of Euro3D Science Workshop, IoA Cambridge, May 200
Sampling of an STT event over the Eastern Mediterranean region by lidar and electrochemical sonde
International audienceA two-wavelength ultraviolet (289?316nm) ozone Differential Absorption Lidar (DIAL) system is used to perform ozone measurements in the free troposphere in the Eastern Mediterranean (Northern Greece). The ozone DIAL profiles obtained during a Stratosphere-to-Troposphere Transport (STT) event are compared to that acquired by an electrochemical ozonesonde, in the altitude range between 2 and 10 km. The measurement accuracy of these two instruments is also discussed. The mean difference between the ozone profiles obtained by the two techniques is of the order of 1.11 ppbv (1.86%), while the corresponding standard deviation is 4.69 ppbv (8.16%). A case study of an STT event which occurred on 29 November 2000 is presented and analyzed, using ozone lidar, satellite and meteorological data, as well as air mass back-trajectory analysis. During this STT event ozone mixing ratios of 55?65 ppbv were observed between 5 and 7 km height above sea level (a.s.l.). Stratospheric air was mixed with tropospheric air masses, leading to potential vorticity (PV) losses due to diabatic processes. The ozone DIAL system can be used for following STT events and small-scale mixing phenomena in the free troposphere, and for providing sequences of vertical ozone profiles in the free troposphere. Keywords. Atmospheric composition and structure (Evolution of the atmosphere; Instruments and techniques) ? Meteorology and atmospheric dynamics (Middle atmosphere dynamics; Turbulence
3-D model simulations of dynamical and microphysical interactions in pyroconvective clouds under idealized conditions
Abstract. Dynamical and microphysical processes in pyroconvective clouds in mid-latitude conditions are investigated using idealized three-dimensional simulations with the Active Tracer High resolution Atmospheric Model (ATHAM). A state-of-the-art two-moment microphysical scheme building upon a realistic parameterization of cloud condensation nuclei (CCN) activation has been implemented in order to study the influence of aerosol concentration on cloud development. The results show that aerosol concentration influences the formation of precipitation. For low aerosol concentrations (NCN = 200 cm−3), rain droplets are rapidly formed by autoconversion of cloud droplets. This also triggers the formation of large graupel and hail particles, resulting in an early onset of precipitation. With increasing aerosol concentration (NCN = 1000 cm−3 and NCN = 20 000 cm−3) the formation of rain droplets is delayed due to more but smaller cloud droplets. Therefore, the formation of ice crystals and snowflakes becomes more important for the eventual formation of graupel and hail, which is delayed at higher aerosol concentrations. This results in a delay of the onset of precipitation and a reduction of its intensity with increasing aerosol concentration. This study is the first detailed investigation of the interaction between cloud microphysics and the dynamics of a pyroconvective cloud using the combination of a high-resolution atmospheric model and a detailed microphysical scheme.
This work has been supported by an International Max Planck Research School fellowship and the Max
Planck Society.This is the final published version. It first appeared at http://www.atmos-chem-phys.net/14/7573/2014/acp-14-7573-2014.html
Mixed Quantum/Classical Approach for Description of Molecular Collisions in Astrophysical Environments
An efficient and accurate mixed quantum/classical theory approach for computational treatment of inelastic scattering is extended to describe collision of an atom with a general asymmetric-top rotor polyatomic molecule. Quantum mechanics, employed to describe transitions between the internal states of the molecule, and classical mechanics, employed for description of scattering of the atom, are used in a self-consistent manner. Such calculations for rotational excitation of HCOOCH3 in collisions with He produce accurate results at scattering energies above 15 cm–1, although resonances near threshold, below 5 cm–1, cannot be reproduced. Importantly, the method remains computationally affordable at high scattering energies (here up to 1000 cm–1), which enables calculations for larger molecules and at higher collision energies than was possible previously with the standard full-quantum approach. Theoretical prediction of inelastic cross sections for a number of complex organic molecules observed in space becomes feasible using this new computational tool
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